Road Bike Disc Brakes Are Coming, But Will They Work?

Are disc brakes safe for road bikes

Me, laying in a ditch with five broken ribs, after total brake failure on a curvy downhill road in Boone, NC.

Disc brakes are coming to road bikes. You don’t need to look any further than SRAM’s new hydraulic offerings as proof; they wouldn’t make it if major frame manufacturers weren’t ready to spec it. But is this progress being driven by the need for improved performance or consumer demand? And are there true performance gains to be found?

After a massive wreck thanks to disc brake failure, I went looking for answers.

What I found, outlined here and in Part 2 (wheels) and Part 3 (frames/forks, articles coming soon) might surprise you. No one seems to argue that they’re coming and that, eventually, the performance will be there. But the tone coming from the people that make the parts is cautionary. People, including me until very recently, tend to think they can look to mountain bikes’ success with discs and translate that to the road. Unfortunately, that doesn’t seem to be the case. At least not in the ultralight, super sleek package everyone’s expecting.

The biggest challenge in making disc brakes strong enough and able to withstand several miles of continuous braking is balancing weight and aesthetics with performance. Let’s face it, if they’re heavy or ugly, you’re not going to buy it.

It’s no secret that several manufacturers are working on road disc brakes. SRAM’s announced it, Magura and TRP are rumored to have something in the works, and we suspect Shimano’s not going to sit idly by. And surprisingly, Hayes has been there and done that. Because no one’s systems (or at least their specs) are official yet, we asked these brands to answer a few hypothetical questions to see how they might address these issues…

Alternative braking: Hit the side of the mountain to go from 34.8mph to 0 in no time flat.

MY DISC BRAKE FAILURE

After a solid three hour gravel road ride led by our friend Joseph from Boone Bike & Touring, we were about to wrap things up with a nice, fast descent down the smoothly paved Junaluska Road. Rolling across the top of the final crest, Evan led the way with me hot in pursuit on my Project Monstercross Moots.

Braking was handled by a first gen TRP Parabox clamping on Ashima’s new and ridiculously light Ai2 rotors. It’s important to note that the original Parabox is meant as a cyclocross brake system. The rear caliper and brake pads are smaller than the front, and the Ashima rotors are about as minimalist as you can get. In other words, they’re perfect for ‘cross where speeds are low and braking is rarely a life or death matter.

Garmin's time capture may not be ultra precise, but we all know it doesn't take long to get going fast. Blue marks the speed, green elevation.

The chart above shows elevation drop and speed. As we began our descent, it took only a few seconds to get up to speed. Being my first time on this road, I kept light pressure on the levers, dragging my brakes to keep my speed around 30mph on a very curvy, steep road. Evan was dropping me on a Canti-equipped Raleigh ‘cross bike, and I was losing Joseph, who happened to be riding the Specialized Disc Crux we have on review and maintaining a more intelligent pace.

Coming around a corner, I pulled my brakes a little harder and the levers went to the bar. I held them there. I was still accelerating. In the span of one second, I realized that a) I had no brakes, b) if I kept descending it was only going to get worse, so c) I better crash now and minimize the damage.

Fortunately, I was headed into the side of the mountain rather than off the side. As quickly as I could, I tried to push the bike out from under me and let it ghost ride. I didn’t think about what, exactly, I would do without a bike under me, but I knew I didn’t want to get tangled up in it at 35mph. That’s all I remember until I stopped, lying in a ditch in the fetal position gasping for air.

The brake fade that led to my accident is something I’ve experienced on my mountain bike on several occasions with multiple brands of brakes. The difference is, on a trail it’s easier to run off the side, skid out or drag a foot to reduce speed. There are escape routes. They may not be pleasant, but they’re not a guardrail or oncoming vehicle. Plus, most trails (other than World Cup DH courses, perhaps) are designed to break up massively fast descents with small rollers or short climbs to keep the rider’s speed in check. Lastly, you’re rarely going 30+ mph on the trail.

On the open road, there are fewer options and arguably worse obstacles. Brake fade or failure there can more easily result in serious injury or death, both due to the speeds involved and because roadies generally wear less (if any) protective gear. The descents are longer and faster. It’s worth repeating: People ride longer, faster descents all over the world every day.

Thus far, I’ve been an fervent proponent of disc brakes on road bikes. There’s still a chance my next new road bike will have them. But this experience has shed new light on some serious obstacles that need to be overcome before I’ll fully commit.

Fortunately, the Moots came out unscathed and its components escaped with minimal damage.

WHAT THE BRAKE MANUFACTURERS ARE SAYING

First, a few assumptions we’re working from: Weights will need to be low, and aesthetics will dictate a small, sleek appearance. All of which minimizes surface area to improve cooling. While DH bikes can get away with 180mm to 200mm rotors and multi-piston calipers, road bikes aren’t likely to see anything over 160mm and single piston designs.

No one wants to tip their hat as to actual product offerings, so answers here are based on the hypothetical scenario that each is or will be offering a hydraulic road brake system. No one would confirm or deny anything.

Here’s who’s talking:

  • Wayne Stetina, Shimano Road Products Specialist (U.S.)
  • Stefan Paul, Magura Bicycle Products Manager (Germany)
  • Lance Larrabee, Marketing Director for TRP (U.S.)
  • Joel Richardson, Hayes Brakes Product Manager (U.S.)

BIKERUMOR: First things first, assuming no leaks or loose parts, what causes disc brake fade or failure?

Shimano: Constant dragging can be death to brakes. Heat causes failure. The smaller the rotor, the bigger the problem. Larger diameter wheels need larger diameter rotors.

Magura: Fade on disc brakes is caused either by glazing pads (the friction coefficient is decreasing, requiring much more hand force to achieve the same brake force) and/or by overheating/boiling of hydraulic fluid, no mater if DOT or mineral oil, leading to spongy feeling and even to the possibility of a full loss of brake power, because the brake lever is touching the bar without pressure point.

Glazing pads can be avoided by following the correct bed in process and having the right compound, matching to rotor material/ surface and heat demands, which is generally already chosen by the disc brake manufacturer. So keep always with original brake pads and rotors.

Boiling oil, that is a compressible fluid, is even worse, because the brake can fail completely. This can be caused by constant dragging and/or steep gradients, pads with low friction coefficient. DOT fluid has a higher boiling point than mineral oil, but mineral oil will keep the boiling point for ever, whereas DOT attracts water over time, even through seals (and its boiling point) will decrease over time and will be worse than with mineral oil. That’s also the reason why brake fluid on cars has to be changed every 2 years.

Having big heat dissipating surfaces is good. Small compact surfaces generate heat build up.

TRP: Heat is the number one cause, whether it’s cars or motorcycles or bikes. And I think there’s potential to get them hotter on the road.

BIKERUMOR: In a nutshell, how do you prevent brake fade or failure?

Shimano: You either get a bigger rotor with metallic pads which can operate at higher temperatures, or you get something like our IceTech that can keep cooler for longer and dissipate heat better and quicker. Even the aluminum flanges on our CenterLock rotors is going to dissipate heat better than a one-piece steel rotor.

Magura: Choosing the right friction parameters of pad/rotor, use original parts, avoid drag braking (short hard braking is better for recovery in between), use big rotors (hand force and pressure to the pads will decrease, thus thermal load).

TRP: You want to have a rotor that’s designed to remove the gasses formed by the pads heating up. Good airflow through the brake will keep it cool. And the last thing you want is for the caliper to get so hot that it vaporizes the fluid. If the heat transfers too much to the caliper, it can boil the liquid.

There's still plenty of pad material left after the wreck. The Parabox comes stock with semi-metallic pads.

BIKERUMOR: More specifically to road bikes, what are the key design differences you had to consider versus your mountain bike brakes?

Shimano: When you take the braking surface off the rim on a mountain bike, you can reduce material there and weight. I don’t believe we can do that on a road bike. If you eliminate the brake surface on a road bike and reduce material, I think you’re going to make it too fragile. It would be unable to maintain its stability.

Weight is more critical. The brake system itself isn’t so much the problem as redesigning the frames for the different torsional loads and redesigning the front wheel to accommodate for the asymmetrical dish. Radial lacing designs won’t work, I think the wheel manufacturers have a bigger challenge than the brakes manufacturers.

It’s not a design difference, but initial designs might be limited because of the upfront investment needed to produce something that may have a limited audience and limited number of frames capable of using them. So the initial cost difference between standard brakes and hydraulic disc brakes might be more than people are expecting. I was told the cost of our original Di2 prototypes were around $30,000 each, so when you really start getting into considering production, you want to minimize the number of prototypes you have to go through. We’re studying this very hard.

Magura: We’re only offering hydraulic RIM brakes for TT and Tri-bikes (at least at the moment, brakes for normal road bikes might follow!?!), no disc brakes. Hydraulic rim brakes are lighter than disc brakes if you look at the complete system. The brakes itself might be equal, but forks and frames for disc brakes have to be beafier and made stiffer to take the loads from disc brakes with their asymmetrical force input. The system of road frame and fork for discs is minimum 500gr heavier than for rim brakes. Weight on disc brakes depends also a lot on the rotor size, the bigger the rotor, the more weight. In order to achieve high heat loads on disc brakes, especially on longer, steeper descents, bigger rotors are neccessary, at least 180mm front, increasing the weight additionally. Rim brakes are more aerodynamic than disc brakes, they can be hidden in the same shape as frame and fork, Disc brake calipers and rotors always protrude the shape of frame and fork.

With rim brakes you already have the biggest possible rotor on a wheel: the rim!

Rim brakes don’t suffer from heat build up/overheating on the hydraulic system, as the distance friction partners (rim/pad) is really far away from the hydraulic piston, so no expansion chamber is even neccessary.

TRP: We’ve done a lot of testing with the Parabox knowing that what started on the ‘cross bikes is moving to the road. With our new system, we’re going with a larger caliper on the rear and we’re recommending everyone use a 160mm rotor on the rear. We’ve cut out some material, but we’re making sure there’s enough material on the rotor to give you both stopping power and enough heat dissipation.

We had to develop it to handle the additional heat that will accumulate on long descents. With road bikes you’re on the brakes for longer period of time and there’s a lot of stress. The amount of grip on road bike tires is more than what most people think, so you do need big powerful brakes. I’ve experimented with a 180mm rotor on the front and it’s nice. Compared to mountain bikes, the piston and rotor sizes are quite similar from what we’ve found.

Ashima's minimalist Ai2 rotors might be great for cyclocross and lightweight XC, but perhaps not for road. Massive discoloration shows how hot my rotors became, they were silver at the ride's start.

BIKERUMOR: Will pad compound or rotor surface materials need to change? Which of the two is more important on the road?

Shimano: No. Generally because the bikes are heavier and the grades are steeper, you would expect there would be less heat build up issues on a road bike. I think technique will help too, riders may need to brake hard for a short distance, for instance coming into and going around the corners, then let off so they can cool. I think in your situation, you were on the brakes the whole time and they simply got too hot. Metallic pads are going to be noisier and take a little longer to warm up, but they’ll work better once things get hot. With IceTech, though, we were able to put resin pads under riders that were previously needing metallic pads and give them better, quieter performance just because they system cooled so much better.

Magura: Pad compound and rotor surface on MTB disc brakes is already on the top. If we had better friction partners, we would use it on both MTB and road.

TRP: We’re not exploring any changes in pad compounds or rotor materials, it’s more about rotor shapes to disperse the heat. The pads in the Parabox are semi-metallic and that’s what we’ll likely stick with.

BIKERUMOR: What about rotor or caliper shape, or pad size – can those dramatically improve performance?

Shimano: They all impact it, and everyone has their own strategy to get the lightest most powerful brake that won’t overheat and still do the job. If you look at race motorcycles or high performance cars, you get multiple pistons or one large one. When you add pistons, you get more twisting of the caliper, which means you need a bigger stronger caliper and rotor. A longer, thinner brake pad will give it more surface contact and friction. It’ll also give you more area to dissipate the heat, and the caliper can be made stiffer. For your size, you might want 180mm rotors and IceTech rotors. Under the same conditions, our IceTech system can run up to 50º cooler.

Magura: Shape and size is already on the optimum for the actual moment on MTB disc brakes. Using the same parameters on road brakes will give better performance on road disc brakes, as the average speeds are higher than on MTB, giving a better cooling effect/better heat transfer into the surounding air.

Increasing pad size would increase weight again (more material of the pad itself and on the caliper to take the volume of the increased pad).

TRP: There will be some new road specific designs, all in the interest of better performance but also in terms of appearance. It’s got to look a little more subtle, and ours will be sleeker than our mountain bike calipers. We’re experimenting with different piston materials and shaping the caliper body to get more airflow through there and radiate the heat better.

BIKERUMOR: Mechanical versus hydraulic discs for road, any performance or safety difference with regards to brake fade?

Shimano: There’s absolutely no difference in brake fade. The benefit to hydraulics is better modulation, there’s a more linear progression of braking power. Plus, the hose won’t get contaminated like cables and housing.

Magura: Mechanical disc brakes will not suffer from boiling oil, but from melting of other components, spongy feeling and bad modulation from mechanical cable and housing. If mechanical disc brakes would be top, then MTBs and cars still would use them!

TRP: You don’t have the fluid issue, but I don’t know that one might be better than the other. You can develop more power with a hydraulic system, and the calipers will compensate for wear, but you have the potential to boil the fluid.

BIKERUMOR: Set up is going to be key. What can you do to ensure OEM spec’d bikes are set up properly, particularly with hydraulic disc brakes whose lines run inside the frame, requiring them to be disassembled and bled prior to the sale?

Shimano: You keep seeing evolution of things where we have the one-way bleed for our mountain bike brakes that makes it virtually impossible for air bubbles to get trapped. Once it goes to the factory, it’s out of our hands. It’s got to be the dealer that’s properly trained to assemble and tune the bike before it gets into the consumers’ hands. All of our systems are sent to the OEM manufacturer pre-bled and are installed. Once they start running hoses inside the frames, it’s going to be a colossal pain in the ass. I think the potential for routing hydraulic brakes internally is not so great because of the one by one labor that would be involved. I don’t know if I’d want that. I guess you could develop joints, like a banjo joint, that could be mounted on the entry and exit points on the frame.

Magura: All Magura brakes, also our RT rim brakes are already designed with service in mind. We use the same tools as on any other of our hydraulic Magura brakes, we use the same Royal Blood mineral oil, we teach our OEM customers how to route lines, how to service, how to assemble. The same we are doing already on the MTB range brakes.

TRP: Every single brake that comes from our factory is cycled 300 times, pressure tested, held for 36 hours, then pressure tested again. Of course, when you start running this inside a frame, that all changes. We’re working on a system that allows you to maintain the pressure in the system while disconnecting the hose. This will allow you run the hose inside a frame without losing pressure (Editor’s note: this is very exciting!).

BIKERUMOR: And for aftermarket sales?

Shimano: You want to take it to a shop that has a lot of experience with mountain bike brakes. Shimano does a lot of hands on training by our traveling tech reps and has online training for dealers. All of this helps ensure they’re set up correctly, and it’s pretty easy to tell if they’re working properly.

Magura: We always recommend: RTFM! (read the f…. manual!). Our manuals always come with detailed installation guidelines. If you follow them, you´ll be fine, even without bleeding. And if you need to service/bleed the brakes, we offer service kits with Royal Blood mineral oil.

TRP: Like our mountain bike brakes, you’ll need a bleed kit if you need to trim the hose. But our new system we’re working on will simplify that process quite a bit.

BIKERUMOR: What about the bike frames themselves?

Shimano: Frames will have to be beefed up to handle the different torsional loads, particularly on the forks. If you just take a fork that’s developed for rim brakes and add disc mounts, that fork is not prepared to take the braking force on one side down at the end. And the rear spacing will have to change to 135mm. It’s a big deal. The other thing that people don’t think about is that you have to offset the front wheel. To handle the narrower spoke flange width, you’re going to either have to add four spokes to the front wheel or about 40g to the rim to make it strong enough. And you won’t be able to use certain types of spokes, meaning it’s not going to be as aerodynamic. As for material, a carbon frame isn’t going to dissipate heat from the caliper any.

Magura: (Answered above)

TRP: Like everything else, manufacturers have taken material away where it wasn’t needed and added it where it was. With carbon fiber, it’s pretty easy to figure out where it needs to be stronger and make it so. You’ll see wheel and hub manufacturers do some interesting things like bigger and thru-axles. Specialized is already aiming their dropouts slightly backwards to keep the brakes’ rotational forces from throwing the wheel out.

And then I talked to Hayes Brakes product manager Joel Richardson. Most people don’t associate Hayes with road bikes, but it turns out they may just have more experience with road bike disc brakes than anyone at the moment:

“About six years ago, we identified the road market as a very good application for disc brakes at a high level,” Richardson says. “We spent a good amount of R&D time and money to develop hydraulic and mechanical disc brakes for a major OEM manufacturer, one of the biggest. After a couple years of development, we hit major roadblocks. The biggest of which is packaging. The current mountain bike brake designs and mounting standards -six bolt rotors, flange offsets, 74mm direct post mount, etc.- just didn’t work for road. All of these were done for a reason with mountain bikes and they work there. The road we went down was a new standard for mounting the brakes. We were working with a major player in the road bike market, but even with their substantial clout, we found that the required packaging of the product didn’t mesh with what customers are likely to want (read: buy).

“What we found with road bikes was that you can generate incredible heat and forces. There are long descents where you’re dragging the brakes for a long time. You have tiny little calipers with very little thermal mass. And they have tiny little pistons that require very little fluid volume. Then you have tiny rotors with virtually no mass that can’t dissipate heat. When you whittle everything down to a super lightweight package, the only place for all that heat to go is the hydraulic fluid, and you can boil it in no time at all. When the fluid boils, it happens instantaneously and it happens right behind the brake pads. As soon as that happens, it introduces air into the system.

“Another thing people don’t think about is, even though they’re skinny, a grippy road bike tire on hot pavement can create a tremendous amount of torque at the rotor and caliper. It’s much easier to lock up a mountain bike tire on a loose surface than it is to lock up a road tire in good conditions, and that puts more friction between the rotor and caliper when braking, and that means more heat.

“The idea has merit and can definitely be executed. We believe in it and know it’ll happen. We’ve built dyno and real world tests around it and spent considerable resources to explore it. At this time, we’re primarily focused on mountain bikes. We have a mechanical road caliper, the CX5, but, well, we don’t have shifters for the road. So here we are.”

will disc brakes on road bikes be able to handle the heat

Tread marks from my cyclocross tires as the bike slid off on its own.

I want to point out that I installed the parts myself, cut the rear hose and re-bled the rear brake and chose to not use TRP’s stock rotors. I do not blame TRP or any other manufacturer for what happened. In hindsight, it was poor parts selection for the actual use. And perhaps I could have used better braking technique – brake hard, release, brake hard, release.

That said, I think it’s not unreasonable to assume most roadies will choose similarly lightweight parts without knowing the performance capabilities and limitations, and many will drag their brakes to limit speed. In the end, all I know is heat was the culprit, but what the exact technical consequences of that heat were on my equipment is unknown other than it failed. And for most riders, that’s all there is to care about.

Stay tuned for discussions with wheel and frame/fork manufacturers over the coming weeks.

Big thanks to Johnny R. for stopping and calling 911, and to Boone’s fire rescue, EMT’s and doctors that took great care of me!

Note: SRAM was invited to participate but has not returned answers as of publishing, which is a shame because they’re the only ones with a publicly announced system. Perhaps they’re keeping quiet until the official launch. If we hear back, we’ll update the post.

Comments

will - 02/14/12 - 11:31am

i read this article twice in the hopes that one of these three representatives could prove beyond the shadow of a doubt as to why road disc brakes are superior to caliper brakes. all the questions that were asked are all very valid and important questions. in my opinion, not one answer given justifies the cost, the weight, the potential danger, the headaches for the shops, frame aesthetics. we all know mtb disc brakes are superior than mechanical and linear pull for mtb. no question about that. but road brakes and road braking are completely different than mtb. keep discs for mtb and cross and leave them off road bikes.

satisFACTORYrider - 02/14/12 - 11:32am

nice read. glad you’re ok. i can see having to design frames and components to accomodate stronger braking forces. pad adjust and return need to be sorted out as well as the heating issues. time to install an abs next to di2!

Steve M - 02/14/12 - 11:33am

Based on the reliability of some of the disc brakes i have used over the years? No thanks. Car and motorcycle brakes are ridiculously reliable. Bike brakes? not nearly. The brake makers are really going to have to deal with the light weight vs. dirability issues. It is not acceptable to have one fail. I run Maguras on my mountain bike and they have been the best. No aftermarket pads, rotors, or bolts thank you very much.

Nice article.

gee - 02/14/12 - 11:35am

that was probably one of the more impressive write ups, glad you are OK, thank you for some sound journalism.

harro - 02/14/12 - 11:39am

great article guys, very insightful

off-roadie - 02/14/12 - 11:40am

Glad to see a post like this. It seems like everyone is crazy about getting hydraulic disc brakes on their road bike without considering if they are even a good idea. Glad you’re ok, good post.

hooby - 02/14/12 - 11:49am

i can’t believe how level headed you are about this episode – that sounds like a horrible experience! And you’re still open minded wrt disk brakes! Personally, I think I’ll hold off for a while before I jump in with the innovators on this one. Great write up.

Dusty - 02/14/12 - 11:55am

Glad you’re OK!
My new road / touring bike has Avid BB7 road calipers (mech) and 160mm discs front and rear mated to 105 levers. I ride in the city, often in inclement weather so I definitely like being able to brake in the snow / rain, which also seems to be the time that many drivers forget how to operate their vehicles.
I haven’t had it out on any big rides yet, but I’ll let you know if they exhibit any problems, (provided I can still type after the carbon fork snaps in half ha ha!)
OK, that’s not funny…

pantsandjacket - 02/14/12 - 11:58am

Wow, that rotor is cooked!

Jon - 02/14/12 - 11:59am

Glad to hear you came out of your crash okay. Thanks for the well-researched write-up. While I’ve no interest in hydraulic brakes for my road bike due to their negligible performance benefit for my riding applications, it’s good to see what manufacturers are doing with the technology.

Whatever - 02/14/12 - 12:01pm

This is actually the first non-PR, and insightful post on BR. Perhaps you are rising a little above my current mental bookmarking as the TMZ of bikes.

That said, I really do think your brake failure is your fault. Have you ridden carbon rims with cork pads? Then you really know brake fade and brake loss. And heat problems. There is no reason your should have allowed yourself to lose both front and rear.

Discs done well on road will actually lead to better road rims. And I’m always happier to be bombing a descent on the MTB vs. the roadie. I think the real cause of you problem is how you set the shimano mechanical to TRP liquid linkage. Funny there are no post of this.

Brendan - 02/14/12 - 12:05pm

First off, sorry to hear about your accident. Second, way to turn a negative experience into a topic for a very insightful post. Keep up the good work, and get better soon!

aint skeerd - 02/14/12 - 12:06pm

Sounds to me like you where riding like a p****, Come on if you ride down hill like that on a rim break you are going to have issues, I ride my mountain bike down maountain paved road reach 45mph and have never had any issues.

ajh - 02/14/12 - 12:07pm

I am glad that nothing worse happened as I see that big rock on the side of the road and am cringing what would have happened if you hit your head on that.

On the subject itself I see the early benefits to those that are doing cross as some wet/mud rides can make brakes basically useless. On the other side of this when the brakes are useless it is usually conditions that if you actually had brakes you would slide out and crash anyway. We also have to be careful as I know, like me, many use a cross bike on the road and may find issues such as yours if not informed.

In the long term I believe that we will have to adopt a lot of changes for disc to transition properly to road. This will be very interesting times and I hope that it is standardized, unlike BB’s today, so that we are not having to change half a bike after deciding to change one part.

Atgani - 02/14/12 - 12:10pm

Whatever

Great to see that having no insight into the situation doesn’t disbar you from passing comment…

I have the impression that Tyler is both knowledgable himself and has knowledgable friends

If there was a “botched” installation, which I doubt, I think his riding buddies may have spotted this

I’m sure that Tyler is grateful for you pointing out it was likely to have been his fault

Can I sign up for your braking masterclass, or are you to busy as a troll?

http://en.wikipedia.org/wiki/Troll_(Internet)

Gordo - 02/14/12 - 12:15pm

I am using Avid road BB7′s and have not had any problems but have not dragged them for an extended period of time. I do agree that modern cars and motorcycles all have hydraulics but they also have motors so I doubt any of them are under built and boil up the fluid. My mechanical BB7′s are not as nice feeling as hydraulics but with no fluid to boil, I don’t see where they could fail on me other then wearing out the pads or warping the rotor. I do agree they are not sleek looking and are a bit heavy but they seem up to the task. Great article and glad you are ok. Cheers, Gordo

Louis - 02/14/12 - 12:17pm

Great article. I think that a lot of the time cyclists, roadies in particular, get really worked up about having the latest and the greatest without really asking why. Do we really even need discs? I can see it being a better option than carbon rim/cork pad braking, but surely it would just be better to go back to metal brake tracks versus the extra complication that comes with a hydraulic system.

Personally, I’m a terrible mechanic. Its not that I can’t do all the stuff needed to keep my bike in working order, I just prefer to not have to do it. I grab a bike and go for a ride. And for the most part this works for me, not cleaning my chain probably won’t kill me. Hell, I can even get away with a few psi below perfect. But it would suck to introduce “bleed or die” into my pre-ride routine.

For now, my bikes remain high end cable actuated shifters and brakes and ultralight aluminum rims (carbon/aluminum for racing). I just don’t think I give up that much by not being on the cutting edge of cycling technology.

Mindless - 02/14/12 - 12:21pm

Luddites are doing it wrong.

Use normal rotor, not this crap.

Topmounter - 02/14/12 - 12:23pm

I live in Colorado and have been riding discs on my mountain bikes for five or so years now. We have plenty of extended, fast and windy descents on pavement, gravel and/or trail. Throughout my 20 years of road and mountain biking with rim brakes (cantis, calipers and v-brakes), I’ve had cables snap, pads fail and a couple rims collapse catastrophically due to a failure of the braking surface. To date, I’ve found disc brakes to be just as, if not more reliable and more predictable than what I’ve experienced with rim brakes (especially when riding in and out of wet conditions).

Regardless of whether you’re riding rim or disc brakes, paying attention to lever travel, braking power, brake fade, odd noises, pad wear and any other tell-tale signs that your brakes may need maintenance or are at their performance limits is always key (the same goes for tires of course).

For the sorts of road riding I typically do, typically a combination of smooth pavement, broken pavement and gravel, steep descents (usually gravel) and unpredictable wet conditions (e.g. afternoon showers or snow melt), I’m looking forward to having the power and modulation of disc brakes on my road bike… of course I won’t be shaving grams by using minimalist calipers and teeny-tiny rotors to impress the coffee shop crowd.

Steve - 02/14/12 - 12:27pm

I’ll probably get flamed for this but…you were using an adapter to make cable brake levers with really, really light rotors. My response reading this was…”not surprised.”

I do not see how insightful this article is with regard to “road disc brakes.” You were not riding “road disc brakes.” When you do, and report on them, I can then see how that report would be insightful to “road disc brakes.”

Mountain disc brakes work just fine under those conditions.

Plenty of folks run BB7s on touring bikes and tandems and log longer descents with much more weight. They do not seem to have the problem you had. Seems like the system let you down…not “road disc brakes.”

dgaddis - 02/14/12 - 12:28pm

Great post.

ajbosch - 02/14/12 - 12:31pm

Great read, glad you came through “relatively” unscathed.

A question though? What is the increase in speed AFTER the fall though?

Eckeecke - 02/14/12 - 12:34pm

@Tyler
Did both of your brakes fail at the same time? Usually only fails first, but if you keep both dragging than it obviously can happen.
Otherwise a very well written and informative article!

JeroenK - 02/14/12 - 12:36pm

Glad you are OK now.

I just do not see in what way this crash provides an answer to the ‘will they work’ question. You have said it all in the second to last paragraph.

**No one is safe with poor parts selection or braking technique.**

There have been accounts of inner tube explosions due to heated up rims, because of brake dragging. There have been cases of brake cable bolts not tight enough. You can get a really wrong brake pad / rim material match with rim brakes too…

I am really sorry, but this story should be a warning to all DIY mechanics above all. The only real risk is roadie mechanics thinking they know what they are doing. It’s all new technology and it’s brakes. Be careful and follow manufacturers’ instructions.

FHS, we all run disc brakes in our cars. The concept is fine.

Vodalous - 02/14/12 - 12:38pm

So, did you try jammin your foot between the frame and the front or rear wheel to slow down (ala brakeless bmx)?

I wouldn’t hesitate to put disc brakes on my road bike. I feel unsafe on my road bike because even with the brakes dialed in, it just takes to much effort and to much distance to stop in an emergency (stupid pedestrians). With my single speed mountain bike with big old slicks I can come to a stop within a few short feet. Thats critical when your commuting acrosss town in heavy traffic.

The other reason I wouldn’t hesitate to install disc brakes is because I don’t worry about over heating. I go fast on my road bike, that’s the point. I don’t hit the brakes on descents, I just scrub a little speed into a corner and hold on. I think for the advanced rider disc brakes have a lot of potential.

mountguitars - 02/14/12 - 12:44pm

awesome article! opened my eyes to how disk brakes are so different between road and MTB. i rode MTB most of my life. i understand the braking technique needed to keep the brakes cool. another thing that could’ve prevented your accident though were the rotors. i’d stay away from ashima’s lightweight rotors. currently, i have the aerotors on the rear of my XC bike, but in the front, i had to change it to something with more surface for the brake pads to grab a hold of (shimano XT 6-bolt rotors). on the aerotors, braking power was strong but modulation sucks, IMO. plus, it ate up my pads very quickly. brake fade? yes! but i replaced only the front since i use my front brakes most of the times vs the rear. you were even using the 2nd incarnation of the aerotors. that even made worse, i think. but hey, its great to know your ok and doing this article opens up a lot of things.

Ralph - 02/14/12 - 12:45pm

Glad you’re ok!

I live in Boone and have ridden that section of road many times. Just so the other readers know, this hill is incredibly steep and unforgiving (sorry, don’t know the actual %). There’s little room for doing on/off braking and it’s virtually impossible to completely let the brakes off given the steepness and curvature of the road. Waiting to brake on this section of road could overwhelm the brakes, as a hairpin turn awaits near the end. I often descend this road on my disc-equipped mtb. In the years I’ve ridden disc brakes, the only time I’ve had my discs heat/expand to the point of becoming completely locked is on the rear brake on this descent (it’s happened different times with different disc brakes–all with DOT fluid). It’s never happened to me during any trail riding under any conditions.

I’m not saying there might not have been set-up issues, but we should also take into consideration this specific section of road (not very long, but very steep and needing fairly constant braking) and the unique circumstances it (and likely others) present for some disc applications.

black dragon - 02/14/12 - 12:55pm

Glad you’re still alive.

Maybe you need next time a carbon composite rotor like the Formula 1 cars ;-)

The Dude - 02/14/12 - 1:09pm

Great article and well written. Glad you are OK. Now go buy new rotors.

Brian Van - 02/14/12 - 1:09pm

I’m sorry that this accident happened to you. I don’t mean to pile on about any errors that may have occurred, but I want to say something to the audience about good braking technique because someone could get hurt if they’re doing the wrong thing:

First off, NEVER DRAG YOUR BRAKES ON A HILL. It literally makes your brakes much weaker at the moment when you need them the most. Even rim brakes are likely to suffer performance loss in that scenario, and you risk serious injury or death.

The proper road braking technique for slowing or stopping over long distances, without exception, is to pump them in short bursts. Grip firmly then release briefly, repeat.

Also, know your equipment very well and don’t make unfortunate discoveries about its limitations on ride day. Test it out in areas where you face little risk from unnecessary hazards – do seemingly tedious things like accelerate to 25mph and test your road bicycle’s full-stop abilities. And in everyday usage, use your testing knowledge and don’t take risks that your equipment cannot handle. If you notice that your brakes are a bit weak and it’s difficult to come to a stop at 35mph on a downhill, then don’t ride at 35mph downhill… begin feathering your brakes at 25mph and don’t exceed that velocity by much. Be proactive in keeping speed manageable, before it’s out of your hands.

It’s basic physics: momentum is the square of velocity, which means that extra 10mph in velocity means a LOT of extra momentum – more than double. The extra speed counts more than you think. You can quite suddenly be in an unsafe situation if you exceed the operating limits of your brakes.

Tyler was fortunate and smart to test his brakes in an area where he could minimize his risk from crashing. Perhaps all that you could do better (other than using the correct braking technique and using the best-quality gear) is to attempt this in a pillow factory.

—–

Also, I think I’m gonna stick with my rim brakes for a while.

Sean - 02/14/12 - 1:11pm

As a Mt. biker that gave road biking a try, I never understood why hydraulic disc brakes hadn’t been adapted to road bikes. This article has raised a lot of points that I hadn’t considered. Thanks for this enlightening information.

mike - 02/14/12 - 1:31pm

i’ve had my BB7s down some really steep road descents with long hard braking…NP. don’t see the attraction of hydros. and rim brakes are worse…melting tubes, popping tires, just another way to break ribs. good write-up.

AlexK. - 02/14/12 - 1:34pm

Tyler choose a ridiculously lightweight setup and then acted surprised when it failed. A couple hundred grams in weight would have alleviated all your issues:
-I use bb7 road calipers and hit 40+ regularly. All this with 160mm rotors. The brakes aren’t the issue.
-Use a bigger rotor. The weight increase is trivial and the increase in stopping power is noticeable. Of all the places you don’t want to skimp on material – the brake rotor.
-I’m surprised to hear that you didn’t have your wheel radially laced as well.

This article is ridiculously biased. Learn to brake properly or buy components that compensate for your ignorance.

Steve - 02/14/12 - 1:42pm

AlexK. FTW!

Gillis - 02/14/12 - 1:55pm

I think one of the problems I’m seeing is the weight issue. Mtb’ers are way more tolerant of heavier parts if the performance gain is there. Canti’s are lighter than discs but we know the braking would suffer tremendously, so we accept the weight penalty readily. That was the case just switching to linear pull brakes (V-brakes). And there was a time even when discs became the market standard that xc racer dudes were still using V-brakes simply because they were lighter. Eventually the weight came down somewhat and they saw the benefit of better braking (that or their sponsors forced it on them).

I can see the road market is going to experience a similar trend. The high end and pros won’t toucdsh it until the 2nd or 3rd generation once all the kinks are worked out and weight comes down. Because the 1st gen is going to be heavier, maybe not work like every one expects them too. The road market doesn’t see as much innovation/experimentation in drivetrain/brakes/etc. Which is why the industry is working so hard to get it right the first time.

All the problems posed above are just problems that will be solved. It’s what engineers are for, its what they do. It’s not a reason to shelve it. I think Hayes problem was that while they identified the market, the market hadn’t been asking for it so the costs couldn’t be justified. I think it’s in a better position to do it now.

Tyler (Editor) - 02/14/12 - 1:58pm

AJBosch – the speed after the wreck is my bike getting taken to the fire station then in my friends car back to their place. I was in the ambulance.

All – I understand that my lightweight parts selection was one of the major causes of this crash. What I’m hoping to illuminate is that the brakes for road bikes will likely need to be substantially stronger or more robust than people may think. Certainly more than I would have originally thought. Information I learned the hard way may help cure ignorance. Stupid would be trying the same thing again and expecting different results.

dan - 02/14/12 - 2:03pm

“disc brakes will never take off on mountain bikes. why bother when there is already a brake surface there? Added weight, added pain and weaker wheels when V-brakes work so sell. Never gonna be used outside of a few nut job DH riders”
my boss and owner of a bike shop/bike company in 1995.
there are a lot of problems with disc on a road bike, but the potential for cool aero designs in a few years seem worth it.
just sayin’ is all…

Greg - 02/14/12 - 2:06pm

I think this article is well written and as someone else mentioned, very level headed given that he broke 5 ribs. I also think its ignorant for many of you to write in that this is user error given that Tyler is an editor/creator of a bike website, its safe to assume he can ride a bike and has lots of experience on bikes. (plus I’m tired of people writing in how they are better riders and don’t have these problems)

Tyler, I like how you have actual data and pics to show for the incident. (not “just riding along”)
I think all manufacturers should read this article as a note of caution. He was descending for less than 3 minutes when he bailed and going over 30MPH. That’s not dragging the brakes for 10 minutes or something extreme and also demonstrates the grade of the descent.

superleggera - 02/14/12 - 2:11pm

Although the costs to do it are expensive (it’s a time consuming process given the manufacturing method) — it won’t be long before you see carbonfiber rotors being utilized. We use on all the racecars and racing motorcycles for a reason — the hotter it gets the better it works. Very light and smaller then a regular rotor setup. Negative is cold modulation but still probably better than existing setups.

Looking at the rotors you used that were so radically lightened — I’m not surprised by the results you experienced.

The biggest problem with disc brakes on a road wheel is the contact patch (tire) to the ground -vs- modulation of the brake itself. It’s just a much easier equation for a mtnbike setup.

Matt - 02/14/12 - 2:21pm

AlexK, while I agree with you that the lightweight setup for this article was a big part of the failure issue, you are also comparing bb7 MECHANICAL brakes to hydraulic brakes. The failure point on hydros will most likely be from overheating the fluid to the point of vaporization which will render the brake useless. You won’t ever get this in a mechanical.

Tyler was already using a 160mm rotor (Ashima Ai2 only come in 160mm and 180mm) but it is highly carved out to shave weight. A less lightweight rotor (with more surface area to dissipate heat) may have helped but I don’t think anyone can say it would have solved that problem. TRP even admitted their new Parabox system has changed to accommodate the added heat for longer road descents – “With our new system, we’re going with a larger caliper on the rear and we’re recommending everyone use a 160mm rotor on the rear. We’ve cut out some material, but we’re making sure there’s enough material on the rotor to give you both stopping power and enough heat dissipation.”

ezweave - 02/14/12 - 2:30pm

I started riding MTB seriously in 1998 (as a teenager) and having experienced the transition from early disc brakes (Rock Shox had some notoriously bad ‘cable actuated hydraulic’ models) to Hayes domination around 2000. Which is to say, I’ve put in serious off road miles on discs in the last twelve years, from winding
and rolling mountain trail rides, to shuttle or lift driven downhill.

It seems like this was a combination of lightweight gear and, perhaps, riding the lever (as has been pointed out).

This has been said, but I think people should realize this isn’t some “I can ride better than you” reaction… it’s a real problem that you end up learning to combat. No brake works well when ridden… that’s just simple thermodynamics. Even my Ultegra calipers on my road bike will have issues on long mountain descents where I notice that it takes more force to stop. You cannot drag any pad constantly, the surface and the pad need time to cool. After all, friction generates heat (all that energy has to go somewhere).

Early on, when I finally could afford a real down hill bike, I learned this the hard way after setting a pair of HFX-9 pads on fire (and to be fair, the brakes still worked enough to keep me from crashing) after a twenty mile downhill ride with a good steep and sharp, technical descent for the last few miles. I had learned to pulse my v-brakes years before (v-brakes have the same friction issues, you only mitigate it slightly by having a thick rim to suck up heat) and had not applied the same techniques to DH riding with “super awesome” brakes.

Oops.

The real problem with disc brakes on road bikes has been one of marketing and weight: competitive road riders are obsessed with light weight and (sometimes) sexy gear (this is a slippery slope as I personally find much of the “sexy” gear ugly and impractical). After all, motorcycles and automobiles use disc systems and do not have these issues (unless you don’t downshift on long descents… I life in CO and the smell of burning brakes from ski commuters in Summit County is a sign of ignorance, not of the failure of brake design).

Also, there is some seriously poor notional general physics in these follow ups. Momentum is mass times velocity. Acceleration is the change in velocity per square unit time. I don’t know how you could mess up p = mv or F = ma, but hey it probably sounds good in the bar.

Steve - 02/14/12 - 2:33pm

It was NOT a hydraulic brake. It was a cable actuated HYDRAULIC ADAPTER designed for CROSS. Not the same. Apples and oranges.
It is ignorant to believe this post in any way reflects what is happening with “road disc brakes.” No “road disc brakes” were used.

David - 02/14/12 - 2:42pm

Glad you are ok now. Thanks for a very insightful write up. The Manufacturers responses were helpful and while I have no doubt it will someday happen, I just cannot see a need when we already have the best rotor size and heat sink already holding onto the rubber… Perhaps the rush to get more carbon into our wheels to reduce rolling weight is part of the demand? Carbon wheels are a lousy brake rotor. Perhaps as carbon fiber (and whatever else comes along) wheels get lighter and stronger a point will be reached where all the parts as a whole will qualify for a large light rotor and caliper system that will work in the manner that road riders are inherently used to applying their brakes (and competition will dictate) in an aero design that won’t compromise speed.

Gillis - 02/14/12 - 2:45pm

I think a lot of you are missing the point in blaming Tyler for his accident or as comparison for hydraulic road brakes. The key thing is that his accident sparked the question:

What are the problems faced in designing a hydraulic disc brake system for road bikes?

Nothing more nothing less. And he went about it in a very respectable way by contacting specialists in the industry.

shabbis - 02/14/12 - 2:45pm

I agree with mike, I have BB7s (160 front and rear) along with Gore Ride-on sealed cables (as must) on my cyclo-commuter and commute in a very hilly area. While the BB7s do require more maintenance to keep them running smoothly, I find the increased performance worth it, especially in the rain. I have a very steep paved road which I descend on my way home from work everyday, after riding my cyclo with BB7s and my old six13 with DA 7800 rim brakes, I’ll stick with the BB7s, especially in the rain. I also apply the disc technique of brake, release, brake, release instead of just sitting on them the entire time. I’ve also stuck with the stock pads and rotors. I would think mechanical discs would be plenty for road and that they should just focus on improving the cooling technology.

SL - 02/14/12 - 2:46pm

Rough bail, hopefully you’re doing a bit better now and not off the bike for too long.

As a mountain biker who’s actually waiting for road disc brakes to become available/mainstream (proper ones, none of this Parabox garbage), it’s interesting to realize that the forces and speeds you can reach on a road bike are able to completely boil brake fluid. It hadn’t even occurred to me that this might be possible. But then it should have, I’ve completely roasted an Avid Code on Whistler. That wasn’t very fun…

As with mountain bikes, there’s going to be an inevitable period of adjustment and rapid technological change when hydraulic discs finally hit the road market hard. Lessons will be learned, gear will improve, and standards will come into play. Will weight continue to be an issue? Sure, but they’ll get there and besides, pros’ race bikes need to hit UCI minimum weight anyways, so why not slap some Shimano discs with Ice Tech rotors and radiator brake pads onto a carbon frame? They’d lower the CG a bit and might help with rotating weight. Add better modulation and all-weather braking to the mix and I still think hydro discs are the way forward for road bikes. On the other hand, it’s entirely possible that hydraulics will introduce significantly higher downhill speeds, which may not result in more crashes, but rather much more severe ones.

One thing’s for sure: 160mm + rotors, none of the ultra light ones. I run 200mm rotors on all of my bikes and it seems like a trend I’ll continue on my future road bike.

stack - 02/14/12 - 2:46pm

I did the same ride as you guys 2-3 hours later that day, and heard about your crash. I want to reiterate to the other readers that road is easily the most technical and difficult descent in the High Country. After years of expounding that all road bikes would have discs one day, this article has really made me question my hubris. Extremely good stuff. Hopefully, I can tag along next time you are up here.

when - 02/14/12 - 2:47pm

I also have cable-actuated BB7s on my road bike. I’ve descended several miles of 10% to the point where the plastic covers on the caliper adjustment knobs melted, but the brakes themselves had no issues. Hydraulics IMHO will have issues with long descents but cable-actuated do not.

Bog - 02/14/12 - 3:03pm

There are many good comments but it seems that everyone here is missing a big part of the puzzle. Not only was Tyler on his CX bike, he was riding with CX tires. In my experience you NEED to drag the brakes more than you would with real road tires because you’ll drift like crazy if you don’t control your speed. With road tires you can carry far more speed through corners and brakes in bursts.\

That being said, I’ve been using disc brakes on my mountain bikes for years and we have more than our fair share of wickedly long descents in the Vancouver area. I’m 240 lbs and many times I’m on the brakes for minutes at a time trying to control my speed and have never lost my brakes. I’ve witnessed brake fade with lightweight rotors so I only use “real” rotors such as any of the models that Shimano makes. They may be a bit heavier but they’re actually designed to handle real world braking unlike some of the lightweight jobbies.

Mindless - 02/14/12 - 3:13pm

I often do 3K+ descends on my mountain bikes, and with a proper setup (I use Formula and Shimano brakes) – there is no fade, there is great modulation, and there is excellent reliability. In the days of V-brakes it sucked.

2012 XT with finned pads have NO fade.

You drag on some really useless rotors and use some poor brakes and act surprised when it is not working.

Disk brakes are much better then calipers. Wait until you can use some disk specific rims – that are wider, lighter and stiffer – then compare system performance.

Bad and misguided article.

Specialized Rider - 02/14/12 - 3:21pm

all im wondering is: a straight, ghost-ride bail was your first choice of escape? no foot dragging attempt at all? You mentioned it so im surprised you didnt try that first. I have been rolling much faster than that and slowed myself using my feet during emergencies or just because it was easier..

oh well, glad you are ok, but I would change the opening paragraphs, title and first picture so it doesnt seem like you are blaming disc brakes for this issue. It seems kind of ignorant to ride such an awkward set-up, using adaptors and ultra light parts and then write a subtle hate column about your experience. Since you have acknowledged the fact that you were about 100% at fault for getting into such a wreck, you should probably update this entry to reflect that if you were to run a standard disc set up and brake properly you will be just fine.

Its not like there has never been canti or road caliper failure.. people dont go post huge articles blaming the industry for their screw ups when that happens, maybe talking some smack about individual companies that played a part.. Blame TRP for having metallic pads that conduct heat, or Ashima for not having their rotors dissipate heat well enough, or blame the adaptor for allowing fade to occur in your system. Or maybe shimano just because you were using their levers that are not designed to be used with disc brakes. or the fact that you were not riding a road bike at all..

In short, this article has some very good questions answered by the big companies about discs in road. Good article with that alone. maybe next time keep to the facts and slip in an interesting story of your personal mishaps related to what your subject is..

Robin - 02/14/12 - 3:28pm

Well, to all those that think this episode is proof of how bad an idea it is to mount disc brakes on a road bike, uhm, it isn’t. First, this is sample set of 1, and it makes no statement at all on the suitability of disc brakes on the road. It does suggest that disc surface area is critical and decreasing said surface area may not be worth the risk of brake failure. This is also another in the endless examples of why you don’t drag brakes for long periods of time. If you drag brakes excessively on a motorcycle or car, you’ll likewise run the risk of cooking your brakes. I do think people will need to accept changing brake fluid each year. It’s not like it’s a big deal and takes a lot of time. It would seem worth the effort ensure the fluid is in optimal condition.

Tyler (Editor) - 02/14/12 - 3:33pm

UPDATE: Not bashing disc brakes for road bikes at all, just wanted to bring some of the potential issues to light. As I mentioned, no blame is placed on any of these manufacturers, and it’s quite likely I’ll make the move to road disc at some point.

Dragging my feet would not have even come close to stopping me safely in this situation.

For the wheels, I was running ENVE 29XC Tubeless wheels with Wheelsmith spokes laced 3x to Chris King mountain bike hubs. Both rotors were 160mm. Tires were Maxxis ‘cross tires, front run tubeless, rear with a tube. Plenty of grip on road and off and a very stiff wheelset.

PDXFixed.com - 02/14/12 - 3:36pm

TED SHRED

ezweave - 02/14/12 - 3:49pm

I should reiterate that Tyler has talked about all the points that I think are valid, it’s perhaps not reading the whole thing that leads to the hype.

I think it really will be commonplace, but so many factors need to change or be adjusted for this application that it’s still in it’s infancy. Mechanical road discs have been around for a while for touring bikes and non-racing applications where size/sexiness is relative and the benefits (greater stopping power, better modulation, wet weather performance, less need for trueness) out weight the cons (weight, aerodynamics).

A race ready solution isn’t really here yet, but wait two years and it will be.

Rich - 02/14/12 - 3:57pm

Glad you’re relatively okay! I’ve ridden down Junaluska…that mess is gnarly! I did it on a CX bike and a road bike, both with rim brakes. With pitches of 24 and 26 degrees and a TON of switchbacks, I don’t know what I would’ve done if my brakes had failed. Clearly everyone who is telling you that you should have done it one way or another weren’t in your shoes and going down a 25 degree slope at 35+ mph. You did well to escape with a few broken ribs (though that still sucks pretty bad).

Either way, the article makes a valid point…not everyone who rides road bikes (or mtbs for that matter) can rip down a crazy mountain descent without proper braking know how. That is something that MUST be addressed, or there will be more than a few lawsuits for the guys that make these. Unfortunately you hurt yourself learning a good lesson for everyone…but all of your readers are very fortunate that you have a giant audience in the cycling community and can bring this sort of thing to light. Really glad you’re doing well, and I hope you get back on the bike soon so you can give Junaluska some hell this summer!

brian - 02/14/12 - 3:59pm

Glad to hear that you survived this episode and lived to write the article, I find it very timely with all the current excitement about upcoming road disk systems. I ride a road bike equipped with bb7′s and KCNC Razors with Avid semi-metallic pads. No issues yet, but I haven’t yet done any descents as intense as yours. So far I’ve noticed that I’m able to brake later and harder than I was on my rim brake-equipped bike.
Did either of your riding companions experience any braking issues – fading, worn pads, etc? What sort of speeds were they riding at?

Rich - 02/14/12 - 4:11pm

Whoops…I meant 24 and 26% grades…not degrees. Either way…it definitely feels like its 26 degrees straight down!

Chris - 02/14/12 - 4:28pm

I wouldn’t trust that rotor on my cross-country mountain bike here in the middle of Florida, let alone on a steep road descent in North Carolina.

Angus - 02/14/12 - 4:38pm

To correct Brian, momentum is in fact mass times velocity. You are thinking of kinetic energy which is 1/2 mass x velocity squared. It is this kinetic energy that you are trying to convert to heat (yes really, something has to get hot for you to stop, it is just a question as to how well that heat is dissipated) in your brakes. The point you make that there is a more than proportional increase in heat generation with velocity is correct, it is just the terminology that was wrong.

FWIW I think road discs will be awesome, once they get them right. I’m not sure I’m prepared to be the guinea pig though.

VICTOR - 02/14/12 - 5:17pm

make the brake rotors/pads carbonfiber

Baba Ganooj - 02/14/12 - 5:26pm

I had a 70s Cutlass SS when I was a kid. Dragged the brakes all the way down Brasstown bald – had nothing at the bottom – very scary. I blew a tire doing some dragging down Lee Hill road in Boulder. That’s all I needed.
Glad you survived that episode.

richard - 02/14/12 - 5:31pm

after reading this artical i am thinking that the hydro rim brakes are the future for road bikes. disc brakes maybe not. for mtb and cross yes! notice that sram is coming out with a hydro brake like the magura and disc brakes may be only for cross??? any thoughts on this????

4biaggi - 02/14/12 - 5:48pm

Very interesting because it is bringing us (me) back to fundamentals; i think i will stick to rim brakes but perhaps hydraulic rim. Less force needed and better modulation. I’ve read all the article and the comments, but nowhere i’ve seen mention of a double rotor on the front wheel like on the motorbikes. So you don’t need large rotors, maybe heat is more manageable and you don’t have asymetric torsional forces on the wheel/fork. I’ve even seen that too on a german prototype bike (canyon?).

Gillis - 02/14/12 - 5:50pm

I tried posting this earlier but it looks like it didn’t go through. This article is not about yea-or-nay. The key thing is that about Tyler’s accident is that it sparked the question:

What are the problems faced in designing a hydraulic disc brake system for road bikes?

This article is about gaining insight into what those are. It will be up to the manufacturers to address those problems and find solutions.

Ed - 02/14/12 - 6:04pm

“I realized that a) I had no brakes, b) if I kept descending it was only going to get worse, so c) I better crash now and minimize the damage.”

Sticking your shoe onto your tire works on a road bike,just as it does on a bmx bike.
Remember this,and your ribs will thank you next time

BBB - 02/14/12 - 6:09pm

A lighter, sexier version of BB7s paired with levers that allow adjustment of mechanical advantage is all most of people would really need. Instead, the marketing guys will be pushing “superior” hydraulic brakes on mentally lazy majority of consumers.

I’m surprised that the author didn’t ask the most important question.
– How will the manufacturers deal with very common problems with hydraulic brakes – rotor rub and sticky pistons?

Kristibee - 02/14/12 - 6:27pm

(Gillis: found it, it’s up now)

IJBCape - 02/14/12 - 6:40pm

Holy cow, glad you are okay. This is a fantastic study on disc road brakes! You can’t get much better data than that.

Awesome post.

postmount - 02/14/12 - 6:46pm

First off, glad to hear the rider is fine.

Relax people. Road tandems have had bb7 for about 4 years now without catastrophic failure. I actually own a disc only tandem for at least 3 years. Keep in mind, road tandems are at least twice the weight of a single bike, and can achieve much higher speeds. Owning disc doesn’t mean its care-free braking, you still have to know how to use your equipment and use it with care.

Based on my experience, it looks to me that the rider: 1) undersized the rotors (if there is any doubt, always oversize your rotors for safety) 2) used light weight rotors instead of a more standard rotor (some cutaway is fine, but I’ve never considered Ashima to be tandem, or DH rated) 3) if the rider is unsure what braking technique he used, then he prob did not use the brakes properly. 4) rider didn’t know the limits of the equipment (disc brakes), even rim brakes has limits.

My conclusion, rider error may be a big varible in this accident with some varible on equipment. Just my two cents. Again, glad he is fine after that crash.

Matt - 02/14/12 - 6:48pm

glad you’re ok

Ian P - 02/14/12 - 6:48pm

For those saying carbon fiber rotors would be the answer, F1 and race cars use something called Carbon/Carbon which work only really at high temperatures and wouldn’t work on anything but steep hills, and other race cars and high end cars (Ferrari, Lamborghini, etc.) use something called Carbon Ceramic which is carbon fiber in silicon carbide. These don’t require a minimum temperature to work and don’t fade. The carbon fiber used in bikes is carbon fiber in plastic which would melt at a low temperature so they would be even worse than these. The only carbon option for bikes would be silicon carbide brakes, but they have problems associated with the fact the material isn’t designed for a small and thin rotor like a bike. I have two prototype silicon carbide bike rotors with me and the final design would be considered massive compared to regular rotors, as the initial design was a 2mm thick 160mm rotor and the ones I have are 180mm and 3mm thick, which is too thick for a majority of calipers. It had to be made this way because the material couldn’t handle the smaller size and thickness without breaking, and they had to be adapted into a floating design and even that wasn’t enough to keep the initial dimensions. Maybe a company could make a material that would be more suited to bikes, but that would take unbelievable amounts of money and I doubt there would be a big enough market to justify doing this. And if you’re thinking carbon brakes would be lighter, think again. The brakes I have are as light as the material will allow and they’re 56 grams for just the friction ring, not including the center spider or mounting, not to mention the pads had to be made of stainless steel and they’re 36 grams per caliper. And if you need a reference to how heavy that is, one of the heaviest pads there is about 20 grams, and the lighter aluminum pads are 10 grams. That may not sound like a lot of weight, but that’s a 75% increase in weight over heavy pads, and the whole system will end up being significantly heavier than just using a plain steel rotor, not even a light one. But the one thing it does have is power and there is no fade, but the downsides are so numerous I doubt they will reach mainstream for a very long time, if ever.

briann - 02/14/12 - 6:51pm

Very glad to hear you’re okay.

Wil - 02/14/12 - 7:03pm

Nothing like a good yard sale on a new bike. Good to hear you will be okay. One thing I wouldn’t mind seeing on these small road specific calipers is a heatsink and/or a vent to direct air through the caliper. I do understand that a rim will always have the largest leverage point of contact versus a disc rotor though that point is moot in the wet, especially with carbon rims. The advantage of not heating the glue on your tubular or bead on a clincher will always make me feel the wait for a proper road disc is worth it. Reduction of material for a brake track will also offset the rotor weight at the centre of the wheel.

WannaBeSTi - 02/14/12 - 7:30pm

I’ve been thinking about this post all day and what could have been different to prevent this type of situation. I really have no answer, but I’ll throw my 2-cents in…

First, I don’t think Tyler is totally at fault, except that he chose some of the worst rotors I’ve ever had on my bike. I’ve had two sets and heat soaked both. I’m not a downhill rider, but I am a hard braker. I can see how these rotors would cause excessive heat to build up and glaze the pads.

Second, I do think brake manufacturers/ bike shops/ customers will have to take into account that all types of people will be on disc equipped road bikes, mechanical or hydraulic. They will not be the cure-all for everyone. A 250lb Fred bombing a descent like Tyler’s will have a rude awakening. Disc will not do any better than rim brakes in that situation.

I have a lot of fair weather commuters with discs complain about their brakes squealing. The only remedy I have is to change the pads to organic (if offered) and to teach them how to remove the mirror finish they’ve put on the rotors from NOT using it in bad weather or getting them dirty.

I have thought for a long time that disc brakes are the next step for road bikes, but it will be some time before I trust them.

Ok, I’m tired and want to go home…

WannaBeSTi - 02/14/12 - 7:33pm

Oh, I almost forgot…

I’m glad to see Marc Alex didn’t have a part in setting up your helmet straps.

Kieselguhr Kid - 02/14/12 - 7:42pm

I’m sorry to hear about your accident and certainly hope you heal fast!

Two points I think you missed:
- This type of failure is not disc brake specific. Heat induced failure plagues rim brakes too; melting the resin on carbon rims, softening tubular glue and clinchers blowing off the rims due to heat build up from braking are not exactly anything new. At least the failure mode of disc brakes leaves you with an intact rim and an inflated tire giving you a better chance to ride the bike out of the emergency.
- Discs do eliminate one mode of failure that rim brakes have: the no-power-in-the-rain issue. Even with Sheldon-Brown=blessed KoolStop Salmon pads there’s always that second or two of “Oh No!!!!! I have no brakes!!!” when you first squeeze the lever with rim brakes.

Also, while you did mention the brakes you used were intended for a different duty-cycle and that you had been dragging them on a long descent prior to their failure you still seem to blame the brakes for the failure rather than the user. Any brake will fail if abused.

Jake - 02/14/12 - 8:03pm

Captivating write-up, a lot of points are brought up – the entire event starting the discussion is terrifying however, and it’s good that the OP is able to look back on it without too much injury.

I personally feel that disc brakes have a perfectly fine home on road bikes, and the manufacturers are probably already well aware of many of these considerations. It probably isn’t a matter of approaching it in a particular way specific to road bikes (beyond obvious physical considerations), likely more simply having the end-user’s intentions in mind. Consider this: In the mountain bike world, the XC guys/gals on their sub 20lb. rigs aren’t going to bomb the downhill course to try and catch a record time with their lightweight stoppers (which would probably be fine up until serious all-mountain riding). He/she would run into similar issues – 30+mph downhill is 30+mph downhill, whether you are on a road bike or a mountain bike, and you must be properly equipped! I for one am figuring that there will also be high-end hydraulic road offerings for these situations – akin to the downhill specific MTB stoppers, we may have some 180mm or 203mm touring rotors with larger calipers, maybe even 4 piston monsters for touring with trailers! People seem to be content with cable actuated systems for those purposes, but I’m sure there would be early adopters, just as there are with lightweight hydraulic road systems now. Anyone that’s angry or upset should get used to the internet, methinks – the OP is writing about his experience, his thoughts, and so on. We can do the same without flaming or trolling (unless you want to have some extra fun, I suppose – the internet is still free – but the site has the right to do what they see fit to keep things tidy).

Fisho - 02/14/12 - 8:36pm

All I can say is I have ridden this road and others in the area which are full on double 100% braking power while your shorts get sucked into your sphincter.

I live in this area, and cannot wait for disc road as I would much rather be replacing rotors than rims and tires melted to the rim. Also consistent braking in the wet as our mountain pop-up showers are incredibly unpredictable in the summer.

The key part of this article:
” I do not blame TRP or any other manufacturer for what happened. In hindsight, it was poor parts selection for the actual use. And perhaps I could have used better braking technique – brake hard, release, brake hard, release.”

Robert - 02/14/12 - 9:00pm

First of all, I would like to send well wishes to Tyler for a speedy recovery.

Disclaimer: I am one of founders of Volagi Cycles – we ONLY produce performance carbon bicycles with disc brakes. Obviously, we have a vested interest in the proper implementation of disk brakes for road use.

We have been testing, riding, braking, and retesting almost every combination of disk brakes since we started our company more than 2 years ago. With that experience under our belt, we can wholeheartedly say that we believe disk brakes not only work better but feel they will make road cycling safer and more enjoyable.

Like any new technology proper design and implementation is key to good performance and a good riding experience. We have experience with every combination of the setup Tyler was using including the Ashima rotors and 1st generation Parabox brakes. We had major concern with both. We felt the Ashima rotors although very light did not provide enough surface area to provide proper heat dissipation and modulation. The 1st gen Parabox prototypes(2- sets) we were testing were woefully undersized and underperforming both in pad size and stopping power.

We expressed our concerns with TRP and are very happy to say that the 2nd gen preproduction prototype of Parabox brakes(with Lyra rotors 160 front, 140 rear) has worked flawlessly and I have personally had one of the best experience I have ever had braking – period. The feel was deliberate, consistent and the control was excellent. TRP has also improved the connection system (mentioned by Lance above) which will eliminate problems that we experienced with air leaks (often during installation), which may have contributed to Tyler’s brake lever bottoming out and not having power at the pads.

We think disk brakes, whether mechanical or hydraulic, when implemented properly, will bring a level of performance and benefit never experienced and are excited to be at the forefront of this revolution. We’re betting our company on it. – Volagi Cycles

Jeff Beck - 02/14/12 - 9:49pm

I’ve been running a Crux with BB7 discs laced via 2 cross 28H to centerlock hubs with 140 mm Shimano rotors attached to a Stans Alpha rim. I haven’t experienced any negative braking affects switching to this bike for road and cross use; I ride on Captian CX 2BR 34C tires.
Only main worry I have is about the high spoke tensions brought on by the front braking forces and the stresses this places on the very lightweight and thinly drawn aluminum rim. To combat this I’m going to experiment with a different rim, the HED C2.
I’ve thought that the braking forces brought on by road would be an excellent place to design rotors using a design similar to those in Formula racecars. I think that these could solve the weight issue and also introduce a great balance of fast cooling and insane power. Maybe we don’t go all the way, but I do think Shimano’s ICE Tech system is starting off in the correct direction. Centerlock is an excellent and clean system that can be greatly reduced in weight (up to 50% reduction).
I view that road disc is a reliable system and it is unfortunate to hear of this users incident. All my wishes to him in his recovery and as always, whenever possible, keep the rubber side down.

Naton - 02/14/12 - 10:49pm

I think one of the key points here is the importance of, as Tyler said, “balancing weight and aesthetics with performance”. You can go on all day about how great your BB7s with 200mm rotors are on your tandem, (and I could tell you how awesome my Hope Tech M4s are) but nobody will be putting those on their new cafe racer for a long time. It could just be a matter of the cycling market getting used to the look? But working in a bike shop, and having seen many customers make purchasing decisions based on looks, brand cachet, and other intangibles, I agree with the OP that road disc brakes will need tsex appeal in order to sell.

Anyway, it’s great to finally have some serious quality journalism on the ‘net. I’d almost forgotten what it was like to read a well researched and thought out article.

Keep up the good work (and ignore the trolls) and interested readers will keep coming back to your site!

Le Piou - 02/14/12 - 11:07pm

” I do not blame TRP or any other manufacturer for what happened”.
Great maturity.
And great article. Clearly one could not happens without the other.

Get well.

PS: stil surprised to read how many sm@rt@ss are here to teach you what should have been done…

IJBCape - 02/14/12 - 11:36pm

Fuck limitations.

saupak - 02/14/12 - 11:53pm

http://www.mapmyride.com shows four switchbacks with an average 10% grade and a maximum of 16% over the last mile of Junaluska Rd near Boone; that’s a good test for any type of brakes on a road bike. Any company bringing road disks to market (in my opinion) will have to give serious thought about how to provide a brake that works with one or more of the top brake/shifter lever systems out there (Campy, Shimano, & SRAM) and that there will be good mechanics and bad mechanics setting these systems up as well as good and bad DIY riders setting these systems up. Even one catastrophic failure that injures, maims, or kills a rider isn’t worth the risk to any company. This is why the big three manufacturers above spend an enormous amount of time developing and testing their products; its why Di2 & EPS took years to bring to market. (And let’s not forget the UCI likes to police new technology in our sport and how long it took the UCI to legalize disks for cross.)
Yet there will still be people looking for the lightest, fastest, most unique components out there for their bikes, people who don’t take care of or maintain their bikes as well as they should, people who borrow bikes, abuse bikes, and push their and the bike’s limits and that will lead to crashes like that experienced by Tyler. It’s easy to point out what Tyler did wrong after the fact, but it happened. We should all be thankful that this isn’t another article about a rider killed, but one about lessons learned from a rider that survived.

Robin - 02/15/12 - 12:22am

A few people have said or suggested that the issues Tyler had that led to the crash are issues that could be avoided with hydro rim brakes. These, however, forget the big problem with rim brakes on descents: managing heat dissipation. No matter how well hydro rim brakes modulate for a given pad size and rim diameter, the same force has to be applied to the rim as would be required with old fashioned cantilever brakes. This would leave CF clinchers (and tubulars to a lesser extent) in the same spot they are in now. On steep descents such as the on in this story, clinchers and tubes on alloy rims can be vulnerable if braking is not done correctly.

We’re going to see a large increase in the number of disc brake equipped bikes offered by frame manufacturers and a concomitant increase in the number of disc brake component offerings in the market. Will disc brakes 5 years from now be improved over what the offerings over the next bring? Certainly. Will they look different? It’s very possible. Will they be lighter? I’d bet on it. For all that to happen though, there has to be a first generation of road disc brakes that all manner of riders use and for which all manner of riders provide direct or indirect feedback to improve follow-on generations.

No matter the case, broken ribs are bum deal, especially if you have funny friends that enjoy making you laugh just to see you suffer.

halfwheeled - 02/15/12 - 12:52am

“Relax people. Road tandems have had bb7 for about 4 years now without catastrophic failure. ”

Ditto! I would say tandems offered full disc option for more than 4 years! I also own a road tandem with disc, Co-motion. 1/3 of the road tandems I see at rallys are now disc and it has increased in numbers over the 25 years I have been riding tandem. I’ve ridden thousands of miles all over the country with the bike: down the Rockies at 40-50mph, and other mtn ranges WITHOUT disc failure.

Having read this article it is pretty clear to me it is rider failure and not equipment failure (highlighting here that my disc set up is several years old). Nothing I am riding is considered high tech, new and improved, uber expensive or lightweight, exotic CNCd anything.

Yes, I’m riding a simple tandem rated BB7 calipers with “boring” SS cables, housing, normal off the shelf avid 200mm rotors, DA STI levers, 270lbs combined rider(s) weight, with NO failures over the last 5 years tandem riding, ZERO. I bet my safety, and the welfare of my stoker with disc brakes.

So: “will road disc work?” Answer: Yes, the cycling industry has already proven the road disc technology works in tandems.

Get well Tyler.

Trevor - 02/15/12 - 1:18am

For those in doubt…

I had a conversation three to four years ago with a staff member of very high end bike shop in central London, saying that effectively what I wanted was a true disc-braked road bike. His argument was that “Campag Records can lock the front wheel. Why would you possibly want anything more powerful?”

Well he’s the expert I thought. …but weeeeeeell, let’s get a test ride to see, just in case. Now, I ride a Cannondale Bad Boy Ultra, a disk-braked ally hybrid on 23mm Continental tyres (Grand Prix 4 Seasons, then 4000s and now Triathlons) and at the time had Formula Oro K18 hydraulic discs with standard, solid steel 180/160mm rotors. So from the test ride and 4+ years of running what is effectively a disk-braked roadie, here’s my take on things…

1) Yes the Campag Records can lock the wheel but

2) they can only do it in the very low speed range (i.e. <10mph)

3) In the 30mph to 10 mph range as tested, they are pitifully underpowered compared to the K18s.

4) When I first got the K18s, the shop told me I'd be fine with 160mm discs and could probably get away with 140mm as I was "on the road so don't need as big discs as off-road". Don't believe a word of it. As Angus – 02/14/12 – 4:38pm correctly points out, kinetic energy, which is what you're trying to rub off with brakes, is 1/2 mass x velocity squared. Got that? Velocity SQUARED. In other words, forget about the extra weight of an MTB rider and kit over a roadie; the roadie's extra speed will have far more of an effect on how much braking power he needs and how much heat he will have to dissipate than will the MTB's extra weight. The effect was that the K18s (with 180s) were adequate until I needed to do …or did ;^) a hard stop from higher speeds, at which point every pad compound I tried …and I tried them all …ended up glazed and from there on until sanded, had a greatly reduced friction coefficient.

5) I have recently fitted Shimano's new 2012 XT BR-785 brake up front with the ice-tech rotor (ally-sandwiched, 180mm). HUGE improvement: far more power for the same rotor size; zero rotor rub; no heat issues thus far; and minimal performance impact from road grime contamination.

6) What about grip on 23mm tyres?
– Never a problem with the K18s
– with the XTs…
– I wouldn't grab a handful on wet, painted road markings.
– I did try a hard stop down a medium-steep hill on good-but-wet tarmac from 38mph and I managed to lock the front end briefly. Now you wouldn't want to do that cranked over, but upright the modulation is fine and you can just release and re-apply. No problems in the dry.
– I had an extended conversation with Conti last month about tyres and they said 25mm is actually a faster tyre anyway (if only they could persuade the racers! <– his words) and will provide more grip and more comfort.

7) What about endovers?
My bike is probably too big for me, with a large frame and LONG top tube. That, flat bars and a short stem means my centre of gravity is further back than will be the case for most road bikes, yet I still lift the back end. i.e. I suspect that for using such powerful brakes on a road bike, frame/fork builders may have to rejig the geometry to shift your centre of gravity down/back or the power will be difficult to use without an endover.

8) Wheels?
36 hole 3-cross on Mavic Open Pro.
I went through a stage of breaking spokes up front but since having them re-tensioned, everything has been fine.

9) Forks?
I do have hefty metal forks. Don't know what effect, if any, that has on heat dissipation. It would be a braver soul than I who'd run carbon forks on 180 XTs in traffic. I must admit I'm surprised that brakes aren't more integrated into the fork given the latter's potential use as a heat sink and/or steerer of cool air.

10) Anything else?
I tell folks I want to stop like Jim Carey, i.e. I stop dead with only my eyeballs continuing forwards. You get the idea. There have been two instances where roadies were a full 1.5 to 2 complete bike lengths behind me and cars have stopped suddenly in front. I stopped as described and I hear "wooooaaaarrhhh" and in each case Mr Roadie is partially alongside. I cannot imagine going back. Running any other brake set-up through London traffic seems suicidal to me. All it takes is a jay-walking cellphone-ditz or some monkey opening a car door or …or …or. That said, there is room for improvement. While the XTs are very good, and I'm not sure you could achieve it without ABS (we can only dream), I'd say they want more high-speed power and perhaps a smidge less when you panic-grab (a slightly flatter power curve?) and I'd like to see a wet-dry setting that I can flip (while on the move, naturellement).

P.S. As for the reason why short, sharp applications of the brake are better than dragging…
If I remember from physics, something loses or gains heat from its surroundings in proportion not to the difference in temp but the SQUARE of the difference, so short, sharp applications of the brake, which generate high, localised heat that is lost quickly to air flow between applications are better than dragging with a slower but, without cooling interludes, ultimately higher heat build up.

Robin - 02/15/12 - 3:02am

How is it that comments get erased?

Fede_Fale - 02/15/12 - 4:17am

Great, so I see in the road bike world aesthetics matter more than safety, since it features so predominantly. Also MTB riders do have their aesthetic obsessions/disfunctional choices but at least they don’t conflict so openly with safety! C’mon who could care the less about aesthetics on such a vital piece of equipment???? Personally I could not say how a brake caliper could ever be made pretty, the MTB ones are just chunks of machined or stamped metal with a “form follows function” approach (while I can see some styling going on in the lever, where is much more easy to do without compromising effectiveness and security). I can understand the need for aero designs, but prettiness…. I mean, are rim calipers pretty? In my opinion certainly not more than disc brake calipers (with the possible exception of the sleek new Magura hidraulic aero rim brakes)

Warp - 02/15/12 - 6:27am

Disc brakes work for every vehicle application, maybe except trains, so I think it’s just a matter of more development before the kinks are worked out.

Glad to know you’re ok.

Isn’t miminum weight already set by UCI and pro’s usually have some kind of ballast (ask Cancellara, LOL!) in their frame to meet the weight limit??

Well, no more ballast. Get safer, heavier disc brakes and you’ll have a UCI legal bike that can brake better than anything else now. However, there is a learning curve for those that haven’t used discs before. They’re definitively not the same as rim brakes.

Kristibee - 02/15/12 - 7:10am

Robin, your last two comments went to spam. Not sure why since you’re a regular, but your comments are up. -Kristi

cmh - 02/15/12 - 7:43am

Coming next month:

“ROAD BIKE INNER TUBES ARE COMING, BUT WILL THEY WORK?”

After experiencing a failure in an ultra lightweight tube after prolonged braking on a steep descent, our author does another FUD piece on the new technology of butyl inner tubes.

Paul - 02/15/12 - 7:55am

Firstly, I’m glad you are Ok!

Having used BB7s on the road many times (including fully loaded touring) across big mountain ranges like the Rockies and Pyrennees, I can’t help but think better braking technique would have prevented your incident and that disc brakes ARE the way forward. I have never suffered from pad glaze with properly bedded in pads, or suffered any loss of feel due to heat in the rotors (being cable operated helps).
I think riding styles and techniques must be re-learnt to deal with disc brakes, no different to learning how to shift properly or corner correctly…

tim o - 02/15/12 - 8:04am

Now I know who’s -still- buying BB7s: trolls.

To the commenters who insist that the author wasn’t running road discs: the ride described (gravel up, pavement down) sounds perfect for… a cyclocross bike. Maybe a cyclocross bike with disc brakes.

In any case, I like that Tyler has admitted poor braking form- though we all know that it’s not always possible to brake in hard, short bursts under all conditions (as the riders familiar with this descent seem to be saying). While I was initially enthusiastic about road hydraulic discs (given carbon’s notoriously poor braking and hydros’ excellent modulation), some of the manufacturers’ comments give me pause…

Troll27 - 02/15/12 - 8:41am

Disk brake failure? I think not.

alex - 02/15/12 - 9:37am

“If it ain’t broke, don’t fix it.” Caliper brakes work very well, in my opinion. I love my disc brakes on my mountain bike, but I really don’t see any need for discs on road bikes.

JonMoy - 02/15/12 - 9:42am

The author made stoopid mistakes, crashed, then wrote the most thorough, unbiased (and yes, mature) article I’ve ever seen on road discs. The information that he shared here might even save lives. Please don’t trash-talk him.

walt - 02/15/12 - 10:49am

The Ashima rotors are unusable and won’t stop you, pretty much out of the box. I’ve tried those things (in 180mm, no less) on mountain bikes and the lack-of-stopping is hilarious.

They are super cheap and super light, and you get exactly what you’d think – a super crap product that doesn’t work. Tyler would have been fine with pretty much any other rotor on the market.

Hihg-zoot ti frame? Enve rims? Ashima rotors? Weird non-standard adapters to activate a hydraulic caliper with a brake cable? It’s like a perfect storm of more-money-than-sense weight-weenie-ism combined with desperate first-adapter disease. No wonder the damn thing wouldn’t stop.

Zap? - 02/15/12 - 11:34am

Title should read: Hey, look what happens when you put brakes on a bike not designed for their intended use!

While I’m glad Tyler is okay, this is seriously beyond stupid. If you’re reaching into new braking territories on untested equipment, it would be advisable (obviously) to test the limits of your equipment in a more controlled environment.

Spencer - 02/15/12 - 11:45am

Essentially the NAHMBS special you are riding and improper braking caused your failure. Unfortunately everything has to be engineered to accommodate that combo. Just like roads could be more fun to drive; bikes could be lighter and higher performance- if we didn’t have to provide for allowances in inane combos. But hey, without guys like you- we wouldn’t have physical examples of what happens when you do what you shouldn’t.

Barrett - 02/15/12 - 12:07pm

Great Article!

Reading the responses from the people actually in the industry really helps shed a lot of light into why the development of road discs for race/sportive bikes has taken so long. Yes, BB7′s have been around for ages, but sticking a mountain bike brake on a tandem or touring bike is not the same kind of application that most road riders will use. A high end, light weight racing bike will have to deal with much different design issues than an overbuilt touring bike will. The frame, fork, and wheel design definitely seem to be the true issues with applying disc brakes to road bikes as it creates a very different set of forces on the bike. Shimano seems to truly understand this, and as always will keep everything close to the chest until it is actually ready to go.

For me personally, I’d be ok waiting til the kinks are worked out with frame/fork and wheel manufacturers before investing in a new disc brake road bike. The brakes will be there, and I’m sure they’ll work great…eventually.

Tyler – Great article, bummer about the ribs. And to all the people who like to preach about proper technique and what not, get a life. The dude runs a website about bikes, pretty sure he knows how to stinking ride. And I mean come on, who hasn’t run a sketchy set up once or twice on their bikes just to save weight. That being said, I’ve seen/experienced horrendous brake fade with brakes used in proper application on mountain bikes. Stuff happens.

Brian D - 02/15/12 - 12:23pm

Sorry to hear about your crash, but let it be a lesson to all of us about lightweight, mixed, inappropriate equipment. Thanks for the great article!

A few things:
Where was Avid in your expert panel?
Please, bike manufacturers, don’t create more potential problems with internal hydro line routing.
I’m going to inspect and service all my bikes’ brakes and wheels.

Unlike cars and motorcycles, we can’t downshift to use engine braking. Maybe someday we’ll have options with an very light electric hybrid system (they exist but are a little heavy for performance bikes). And another dream option…ABS.

harry covair - 02/15/12 - 12:27pm

fancy parts does not a good rider make. i feel more sorry for the bike. i mean, look at the bar/lever position in the photo. its halfway to a DUI bar. im guessing the bike probably didnt fit that well to begin with. its hard to push bikes to their limits when youre not comfortable.

Tyler (Editor) - 02/15/12 - 12:58pm

Harry – the bar was knocked into that position during the crash.

dbikes - 02/15/12 - 1:02pm

I have great experience with hydraulic disc road bikes, since I’m offering since 2010, under the label „DBIKES“, ful carbon super light hydraulic disc road bikes, please look at http://www.dbikes.de (english version is in preparation).
I have sold a number of such bikes in germany and switzerland and none of my customers has reported similar problems. I, for myself, have ride about 5000 km and about 50 000 meters of altitude with a 6.9 kg hydraulic dic road bike, Ashima 160 rotor front and 140 rotor on rear. Conclusion: Hydraulic disc road bikes are working very well on street, similar to hydraulic MTBs on street, with one main difference: Using the rear brake a little bit strong, the rear wheel has a relative fast tendency for gliding. Therefore, I’m using nearly exclusively the front brake on steeply sloping streets. We have sufficiently experience with two braking systems:
- Trickstuffs „Doppelmoppel with Cleg 2hydraulic disc brakes
- Formulas R1,which allows, in combination with the mechanical „DBIKE“ – converter the using with all commercial road racing controls (http://www.dbikes.de/?rub=11).
In rare cases, after long time braking, the front brakes showed a little fading, but in all cases we have had enough time to change to the rear brake, for a few seconds.
In the case that the BIKERUMOR-Redaktion would like to test one of my hydraulic road bikes, this would be no problem. Please contact my directly.

Willgis - 02/15/12 - 2:36pm

I’ve had rim brakes fail on me under similar conditions. Wasn’t going as fast, but my brakes completely gave out on me during a hairpin turn on a descent that dropped 800 feet in a quarter mile. With rim brakes, the pads can completely glaze if you’re not proactive about keeping them fresh, so that’s a whole other issue. My experience is that having more powerful brakes (discs) allows one to use better braking procedure (not dragging) with less hand strain.

Brett - 02/15/12 - 4:59pm

You can tell this article is good based on how many comments there are and how everyone has chosen a side.

Hope you are healing up.

Urban - 02/15/12 - 5:05pm

Guys, as a sometimes-roadie and sometimes MTB downhiller, I’m not buying the idea that a road bike brake will get hotter than a mountain bike brake. With very few exceptions the road bike will be moving at a higher speed which will result in (1) more air drag on the bike/rider and (2) better cooling from more air flow over the brake system, both for a given vertical drop. Of course, I have never seen road descents remotely approach the steepness of a MTB downhill run. If the road bike brake is getting hotter, it is simply because you are riding down bigger hills then you do on your mountain bike.

The off-color “burnt” rotor has happened to pretty much every MTB disk brake I’ve ridden down an actual mountain.

postmount - 02/15/12 - 8:30pm

In regards to the comment that tandems are overbuilt, perhaps 20 years ago they were overbuilt, but todays tandems are engineered in the same way as single bikes. Here are some facts to consider:

28lbs tandem = 14lbs (x2 riders) = 14lbs single bike(with disc)
How many 14lbs single disc bikes are out there? Let alone how many people are riding a 14# single rim bike on a daily basis?

2000gram Rolf Vigor disc wheelset = 1000 gram (/2 riders) = 1000 gram single road bike wheelset
Again, how many of us are riding a 1k gram disc wheelset on a single bike?

Another false claim is that tandem just stuck a mtn bike BB7 on it and called it the day. Wrong. It is a road specific caliper, not a mtn caliper.

So when you start looking at the complete picture, tandems are pretty amazing example of engineering that single bikes can easily borrow from and scale down. I have yet to see creditable evidence why tandem disc are not a valid case study for future disc road tech.

Also, consider Santana tandems did offer a cable to hydro converter (sim to trp) for their tandems back in the 90’s yet today mech disc is the preferred brakes for tandems and I have yet to see an old Santana converter in use today. Does this mean road bikes will repeat this? Who knows, but it is important to review history, case studies, and precedence to back up opinions with facts.

It’s also interesting to read that Volagi Cycles essentially concluding the SAME conclusion as myself: rider error, poor parts selection, inappropriate use of products.

someslowguy - 02/15/12 - 9:54pm

1. what a jerk – taking you on a descent like that without warning. tisk tisk

2. willgis – where did you drop 800 feet in 1/4 mile?? was this on pavement??

Kevin - 02/15/12 - 11:49pm

Tyler, thanks for the insightful article and sharing some common overlooked mistakes with the introduction of road disc brakes. Should I brow-beat you like so many others already have… no… as a cyclist I know first hand about pushing the body and equipment further than it should go. As humans we always test the boundries, how else do we evolve. What would be irresponsible and ignorant would be to do the exact same thing again and expect a different outcome. I am thankful to hear that it is only your ribs and nothing worse. Hopefully the Moots frame came away unharmed.

richard - 02/16/12 - 1:39am

the main problem seems to be that braking was prolonged. being a pro xc rider i feel that the road bikes have longer duration’s of braking. the speeds of both can be very similar. i have gone 45 mph on mtbs so speed is not the issue. it is the time on the brakes that kills them. i think that they need to find a way to channel air toward the brake at say 30 mph there might be enough to actually cool them somewhat???

dez - 02/16/12 - 6:04am

since when does a lightweight rotor like that help the heat problem?

Angus - 02/16/12 - 10:25am

To those arguing that a road disc cannot possibly get hotter than a downhill mtb disc because of the cooling effects of the speed, the duration on the brakes etc., you have valid points. To my mind however, one of the major factors in this is that the 2 brakes you are comparing are not equal. You do not have to ride up the mountain with the downhill brake and can have massive rotors, larger pads and cooling fins.

Try riding a downhill course on a road or even xc disc and you’ll have heat dissipation problems.

Tomi - 02/17/12 - 5:26am

Is he a new cyclist ?

Whatever the vehicule/type of brakes, every experienced drivers/biker/rider knows that you shouldn’t drag the brakes constantly on long descents. You learn it at driving courses too. A bicycle+rider is so light it has enormous stopping power, you only need to use brake in the last 200-100m before the corners depending on weather and road conditions.

I never used a disc brake system but it is just common sense whatever system you choose.

banjo - 02/17/12 - 1:41pm

As the Hayes guy stated the main problem is heat and boiling fluid in a hydraulic system. I used to race motorcycles and there the brake fluid mattered most. In hard braking bad quality fluids boil really easy and thus generates brake fade.

But this can be eliminated by using quality brake fluid like motul RBF600 or similar and changing the brake fluids regulary. In premium fluids the boiling point of the fluid is much higher. But you have to look out for the water that condensates in the fluid and for that you have to change brake fluid in regular interval. Some motorcycle racer change fluid after every race, because the feel of the lever change as the fluid ages.

In motorcycle stuntriding the brake fade problem is also present and many prevent it by using premium fluids. The boiling problem is similar as in your situation where you had to drag the brake a long time. It would be interesting to test if the culpirt was a bad fluid used, of course in a lab environment.

Glad you are ok. I really hope that the manufacturers address this issue, before they start selling these systems to road bikers.

whambat - 02/19/12 - 10:21am

Tyler-
Glad you are ok, crashes at those speeds can be very deadly. Many of us have seen similar situations with rim brakes on the road and know how scary it can be regardless of types of brakes. Remember the classic moment in the Tour when Beloki’s tubular tire glue failed from the heat, partially due to braking heat. That crash cost him his career.
In the interest of full objectivity, maybe you should include the comments from Volagi Bikes into your article. An anti-disk brake article could seriously hurt their bottom-line, they should be given an ability to defend their concept into your article, not just the comment section that many do not read. I have no affiliation with their brand, but I do root for the direction they are taking cycling.
In my opinion, road discs would have a serious benefit to road racing as carbon rims provide really poor braking, even with proper pads, especially if you weigh more than 165 lbs. Mountain descents in the rain make it especially dangerous. In an era when mechanics add weights to road bikes to meet UCI minimums, disk brakes could be a welcomed safety feature, if done properly. For the amateur racer, it will also make it easier to switch between training and racing wheels. Also, with the popularity of 29ers, a move to standardize all hubs to 135 would be very welcome.

DrDoodles - 02/20/12 - 9:18am

Wait! It turns out lighter and newer is not always better? WOW! Imagine that. Instead of letting glossy ad marketing and absurd internet commentary decide what components we use let’s go back to that good ol’ default: common sense. We are all glad to hear that you are not badly injured and thank you for at least starting this debate. I don’t have the time and patience to listen to most of the drivel people spew but here are some thoughts. Cross bikes on contrived courses don’t generally go go that fast; road bikes do, and mountain bikes (properly piloted) can. Thus, bigger rotors are a good idea. And while you’re at it, use a real one not a piece of aluminum foil stamped over a Christmas ornament. Not rocket surgery is it? Cars, trucks, motorcycles, mountain bikes/cross bikes that I ride regularly go 50mph down twisty roads, trails etc with not a thought about their reliability.. and out of the hundreds of mountain bikes I’ve sold or serviced I have never heard of total disc-brake failure. There is a lot more substance to say, I know that, but most of you won’t listen or understand anyway so why bother? Reading these articles one can occasionally gain insight, but sometimes I seethe with rage and this is cathartic. One more thought; if you have no direct experience with what you are talking about then shut up! Speculation and whatever you overheard on the group ride is not helping!

Devo - 02/26/12 - 11:52pm

Hey Tyler:

Bummer you stacked the bike. Get better soon. I love the website, read it every day. Ironically I did not read this article until today. Be careful out there. Let the crash test dummies to their part.

d-

Sean Melchionda - 03/09/12 - 4:36pm

Every high performance vehicle on the planet (except road bikes) use disk brakes. Its about time road bikes get them. The idea that you have to redesign the disk brake for a road application should be obvious. Of course a mountain bike disk brake on a road bike is going to be heavier than a road caliper brake on a road bike…. Once the manufacturers design the road specific versions they will be lighter and better than what we have now.

Also the idea that we don’t need disk brakes on road bikes I completely disagree with. Have you ever work out your braking surface on a set of wheels? Have you ever ridden your bike in the rain? Have you ridden with carbon wheels? Have you ever ridden with carbon wheels in the rain? Anyone one or all of those experiences will teach you that its time for road bikes to grow up.

To the author of this article, I’m glad to hear you are ok… but why on earth would you use such a minimal brake disk? How many grams did it really save you? Disk brake power is all about swept area and your disk doesn’t have any.

jason - 03/13/12 - 11:35am

” And perhaps I could have used better braking technique – brake hard, release, brake hard, release.”

Perhaps? There isn’t any doubt that your technique made the problem worse. Every one of your experts told you so. And next time your lever goes to the bar, pump it don’t just hold it their.

Road disc brakes have a niche to fill in road cycling but I would be shocked if we ever see it wide spread in the competitive segment of the sport.

George Krpan - 03/16/12 - 2:32am

I ‘ve been using Avid BB5 Road mechanical discs, 160/140mm rotors, with Dura Ace integrated shifters on a disc only monstercross bike for the past four months for road riding.
I have not experienced fade and I live in a hilly/mountainous area and weigh 200lbs.
They are better and stronger than any rim brake. The pads need to be kept adjusted close to the rotors for the best modulation. Adjustment is super easy and quick.
I abandoned hydraulic discs on my mountain bikes long ago. They are NOT way better than mechanical and are more problematic.
Most roadies I meet are totally naive about disc brakes and are under the impression that hydraulics are way stronger. It is just not so.
Go mechanical, use the shifters that you already have.

phylos - 04/30/12 - 5:04pm

Smokey Yunich published some testing in the late 50s/early 60s, but Jaguar had it figured out long before then. The advantage of disk brakes on cars and aircrafts is better heat dissipation than drum/internal brakes. They don’t provide better braking (actually somewhat less efficient, all else being sort of equal).
Having small, lightweight rotors on a car – or a bicycle?- is a prescription for heat-related failure. You don’t see tiny thin disks from a Camry on race cars, even though the Camry weighs more. Porsches have big heavy vented rotors (actually, now they have ceramic rotors). Same principles should be true on bicycles.
Disk brakes seem ideal for mountain bikes and commuters, where relatively slow speeds and intermittent loading in all kinds of conditions are imposed. And, ultimately the brakes are only as good as tire adhesion on the road. In the dry, the V-brakes and disks on my two commuter bikes work equally well, the tire/road interface is the rate-limiting step. In the wet, however, only the disks offer the possibility of wheel-lockup and therefore offer me maximal braking (with careful modulation).
On road bikes meant for speed though? No matter how you use the brakes, the energy to be dissipated is the same between any starting and ending speed. Total heat release is the same, speed=heat. Maybe roadies will have to learn what motorcyclists and rally car drivers know, the best use of the brakes is a controlled hard application for the shortest possible time. Gradual/continuous braking builds up heat and uncontrolled hard application upsets the vehicle’s dynamics or breaks the tires’ adhesion.

Loki - 05/18/12 - 2:04pm

Maybe I missed it but not a single post brings up the point of higher rated fluid. The DOT rating on fluid is directly related to the fluids boiling point, or more to this application, it’s ability to not vapourise, leaving you with no brakes. Worried about your brakes failing ? Run DOT 12 fluid. It’s a little more expensive but you’d have a lot more headroom for questionable braking habits.

engineer - 07/02/12 - 10:25pm

Consider the history of car and motorcycle brakes. Cables led to hydraulics. Did cars and motorcycles go back to cables? NO (hydraulic lines are even used in clutches on motorcycles such as KTM)

Hub breaks led to disc brakes on cars and motorcycles. Did cars and motorcycles go back to hub brakes? NO

Road bikes will have hydraulic disc brakes. They might need to be bigger than people want (at first) but they are superior in almost every way, especially safety.

John lewsey - 07/06/12 - 11:27am

Hi I’m a road cyclist and mountain biker I can’t wait for disc brakes on road bikes .it has to be safer . people don’t seem to understand it isn’t only obout the power of the brake it’s about the feel of the brake the control .When I get back on my road bike after riding my mountain bike I always wonder what’s happened to my brakes .the other point is that you don’t see the motor cycle industry queuing up to fit rim brakes and lets face who wants a brake that doesn’t work when it rains I’m amazed that they are allowed to to sell a road vehicle fitted with them

Jason - 07/08/12 - 9:47pm

Glad you’re okay.

Looking at the photos of the Ashimas, a mountain biker would’ve thought “deathtrap”- just too much of the braking surface is missing for serious road descents.

I’ve just moved to road biking from mountain biking. I’m impressed with how strong road bike brakes are, but still look forward to discs being adopted- the wet weather performance of discs is more consistent, and moving braking material from the rim to nearer the hub should make for snappier wheels.

Nathan - 07/25/12 - 1:33am

First off, nice right up! Sorry you had to endure this to be able to shed some light on the subject.
I’m relatively new to road bike disc brake setups, and not sure if this has been covered yet, but I’d like to take a page from motorsports, and share my thoughts.

Slotted rotors prevent glazing of the pad surface by shaving away the glazed layer of pad material. But having enough surface area for pad/rotor contact is crucial. Also, pad composition is probably the most determining factor of brake performance outside of tire grip. Pad composition will also regulate fade properties. Whether or not the brake actuation is cable or hydraulic really isn’t the major concern here… It’s rotor and pad materiel.

Also, using a brake fluid with a higher boiling point will also reduce fade and help with lever stiffness… Which will intern provide better brake modulation. This is the fluid I use in every hydraulic system on my car, and should carry over to a road bike/MTB brake disc application very nicely.
http://www.precision-sport.com/motul-rbf660-racing-brake-fluid

St.John - 07/31/12 - 3:27pm

I´m not shure if this brake failure is a question of mechanical or hydraulic calipers.
I also tested the ASHIMA Ai2 rotors on my cyclocross bike. First with a HOPE V-Twin with HOPE X2 Race Calipers (hydraulic) and than with BENGAL MB700T (cable). In both setups the 160 mm Rotor showed very strong fading during my tests on a steep road, where I accellerated to 50 km/h and than braked only with the front brake until I stand.
With normal weight rotors and also with lightweight rotors like Windcutter I need approx. 23 to 25 m stopping distance. With the Ai2 rotor it took 36 to 40 m to stop. The feeling at the beginning was ok – strong braking, but suddenly the deceleration felt much lower. All results are based on minimum 10 repetitions.

I came to the result, that the ASHIMA Ai2 is a very light rotor for use in cyclocross races without steep descents, but not on normal roads or for offroad use, where a reliable stron braking power is a must.

O. Emry - 09/14/12 - 1:47pm

It’s not about stopping power; it’s about heat dissipation. Any brake that can lock the front wheel (skidding it or raising the rear wheel as road conditions allow) will have the same stopping distance as any other. Any brake that _can’t_ do this (with useful modulation) isn’t worth further discussion.

Long-term braking on descents requires dissipating gravitational potential energy as heat, and this is proportional to your mass and your vertical drop. Compare a car’s mass to that of its brake rotors. Do the same calculation for your bicycle’s brakes and it’s pretty clear that this is not a reasonable system. The pictured rotor with only a vestigial structure takes this to a logical extreme.

This reminds me of the people who machined the cooling fins off their tandem’s Arai drum, gleefully claiming it still had the same stopping power. Of course it did, but it no longer was capable of dumping massive quantities of heat–its only reason for existence.

I’ve warped front rotors on downhills, and I’ve seen several of them on tandems. Rotor collapse was not far behind, which for a front wheel would be a guaranteed catastrophic crash. I don’t want to beta test this stuff for manufacturers.

I’m done with discs on my touring bike, and I have no desire for them on my road bike. Kool-stop salmon pads on AL rims work well enough in all conditions, and weigh less to boot. Yes, I have to contend with tires blowing off rims on steep descents, but there is more margin there than for paper-thin 200g disc systems.

AndyBaker - 10/29/12 - 5:56am

The first comment summed up my immediate thoughts exactly – what are the advantage of disc brakes on a road bike as the list of disadvantages seems to be as long as your arm.

I ride both MTB with disc brakes and a road bike with rim brakes. The rim brakes on my road bike are *much* more powerful that the brakes on my MTB – although I admit the disc brakes are not the best available.

To my mind, disc brakes on an MTB solve a specific MTB problem which is that the rims are often wet and covered in grit / mud – reducing braking efficiency and accelerating rim wear.

Another thing I’ve found with various disc brakes in the past is that they squeal loudly and embarrassingly when the rotors get wet.

Jimjam - 11/07/12 - 10:08am

Look at the Colnago C59 with Formula discs. Has anyone heard or seen any issues with it?

Dolan - 01/19/13 - 1:01pm

Great article! Overheating issues are quite common with disc brakes. Many mountain bikers with light XC brakes have also learned this the hard way.

I know Tyler must have heard a million times what he did wrong. But was there anything to be done to prevent the crash after realizing the fade problem? The best I could come up is this: Immediately release the rear brake to allow it to cool down. Lightweight brakes heat up quickly but they also cool down quickly, so a second or two might be enough to accomplish the next step. Move weight to the front wheel in order to lighten the rear and slam the brake. Hopefully there is enough bite to lock the wheel and start a skid. When skidding, there is no heat generated in the brake so it continues to cool down. If the rear starts to slide sideways, release the brake momentarily to restore control. Use on/off braking+skidding only, no dragging. Skidding is not the best way to slow down but it is better than nothing. By now the front brake has probably heated so much that it provides negligible power so you might as well release it. Pump it from time to time to check if any power is returning.

The feasibility of this method depends heavily on the actual situation. If the road is too steep and curvy and there is too much speed to begin with, it probably will not work. And it requires that the rear brake recovers enough to start the skid. Hypothetically one could lock the rear wheel with a shoe, but then keeping a skidding bike under control while a foot is jammed between rear tire and seat tube sure is something not included in every rider’s skill set.

Ken - 01/26/13 - 7:17pm

I had a similar experience on a bike, years ago, with cantilever brakes (long before discs were ever thought of on bikes). I was headed downhill lickety-split with rain pelting down. On application of the brakes, I soon realised didn’t have any (well, I did, but the layers of water on the rims reduced the coefficient of friction so much that I wasn’t even slowing, let alone expecting to stop). So I did the same thing. I just laid down and the bike and I slid to an eventual stop (I was on tarmac in a suburban, traffic-less, street). No injuries and no damage. I have always been hesitant about riding in the rain since then – not necessarily because I don’t like getting wet, but because the brakes don’t work as well.

Having said all that my newest bike has (against my initial desires) disc brakes, and they have been nothing but trouble. They kept failing on me. I went back to the bike shop at least 5 times before they replaced the calipers, finally admitting a fault of manufacture. Now that they are sort of working I find I have to change the pads, because they have worn (I do ride up and down hills a lot – so they get a decent work out). I wouldn’t call myself a dinosaur, but I just think that rim cantilever brakes are better (which my other two bikes have). After all it is easier to stop a wheel by braking at its rim (where tangential speed is lower) than at its hub.

Sam - 02/22/13 - 1:48am

I can’t believe that you actually expected those rotors to hold up. There’s nothing to them. I’m glad you were able to walk away from the accident, but seriously, don’t skimp on the most important part of the bike and you wont have these problems. I don’t have a road bike yet and the one reason I don’t is because of the lack of disk brakes. Rim brakes are just too unreliable especially in wet conditions.

pedalbarron - 03/05/13 - 2:03pm

If bike manufacturers want a real challenge try safely stopping a road tandem, 400 pounds of load going 50 mph. That will stress any braking system. Also, let’s do it in a way that allows for S&S couplers on the frame.

Chad Shanks - 05/14/13 - 8:40pm

Let’s start with those rotors…..complete joke. Those rotors are not allowing much surface for the brake pads to partner with. No way would I run those things. Secondly, what we aren’t hearing about is all of the people who do not work for bikerumor whose HUNDREDS if not THOUSANDS of rims have failed from over use on a rim brake, if you don’t believe that doesn’t happen, then you are just wrong. Rim brakes are fine if a person re-laces their rims every 5000 or so miles, but that simply doesn’t happen making the rim thinner and thinner, until one day, the brake surface just blows out. It’s happened to me and just about every co worker that I have had in the last 14 years that I have worked with in shops. Admittedly it happens much less, as most of those cases were on mountain bikes, but the last scenario was my current co-worker whose rim gave up on a descent only going slightly over 20….luckily he rode it out.

A Munshi - 06/30/13 - 1:22am

Never, ever fool around when dealing with the laws of physics.
If you do, then expect profound consequences and proceed accordingly.
If you do proceed (as a test pilot would), make sure that a qualified engineer has done the necessary quantitative analysis and you have a few well-practiced exit strategies ready to deploy.

Brave article, thank you. Good fortune. Bad conclusions.

First, all braking systems will fail under heat stress, the question is only how much stress.

Heat stress is maximized under mid friction conditions because the energy dissipated goes as v-squared, while heat loss goes up as brake temperature minus ambient temp (one is squared and one is linear– both are Newton’s laws — high school physics). Therefore the temperature rise in braking can be enormous. The equations explain why hard braking to quickly drop the velocity is preferable to riding the brakes.

Your system failed under heat stress due to prolonged braking. If the ambient temperature had been lower your system would have lasted longer.

So if you go DIY on a critical system and do not qualify it, expect a disaster. That this was a DIY disc braking system is incidental, it could have been a 3D printed handlebar stem.

Bad implementation does not negate sound technology. I’m pleased that all manufacturers responded professionally and with restraint.

Indeed, DIY OR NOT, braking systems are inherently self-destructive. If you ride at speed you should routinely practice emergency procedures.

1. always apply the rear brake first and stagger the engagement of the front brake whenever possible
2. Never cook your brakes (riding brakes is bad even for a car).
3. Foot braking, foot on wheel or heel against rear spokes are good emergency manoeuvres to practice in hilly areas.

Finally, always do a quick bike check before any ride, particularly long or technical ones.

Be safe.

David Chutter - 07/22/13 - 12:35pm

Firstly, Tyler I hope you are feeling better!
I have been looking into the possibility of switching just my front road brake to a mechanical disc. Based upon articles posted on bike rumor, numerous conversations with rim & wheel manufacturers(Enve Composites), brake & component manufacturers (Shimano & Sram, Ciamillo-Zero Gravity) & hub manufacturers(Chris King & White Industries) & bike frame manufacturers(Litespeed), I have found that that the answers are still up in the air. The technology is certainly available, but all these companies seem to be waiting for someone to make the first move.
Bike Rumor recently posted an article regarding Shimano’s announcement of their first road disc brake system. Interestingly enough, when I called Shimano, their tech Support stated that it would not be backward compatible to any other drivetrain systems. Hub makers like White Industries have just released a 24 spoke front hub that is disc brake ready. Chris King now offers a 28 hole disc brake hub as well. Enve composites makes a disc brake road fork but doesn’t have a 24 spoke wheel to go with it.
In regards to the bike frame makers, Litespeed is still not prepared to build a disc brake ready Ti frame. I did however see a really nice Colnago road bike built up with Sram Red 22 & Formula disc brakes.
There is no doubt that road disc brakes are coming. I guess we will all have to wait until this year’s Interbike show, to see what is still behind closed doors .
Now what about a lightweight, internal hub?…………. Hello-Shimano, Chris King, Doug White anyone?!

Richard - 09/27/13 - 10:20am

I wonder how this will effect touring bikes. I’m currently investigating and have been looking at hydraulic disk based systems. I currently run V brakes and had a recent problem in the wet when a dog ran out in front of me and that wheel revolution or two before the brakes worked meant I came very close to hitting him.

Touring bikes will see greater weight than road bikes, but can accept heavier duty aesthetics to cope with this. Our touring tandem has a third brake which is a drum with a huge black finned heat sink on it. We’ve not seen it fade, but do allow it to cool when we can.

Only some touring manufacturers currently provide frames that can take disks. The ones I’ve seen have specified 160mm rotors, where larger would seem sensible at least on the rear. Could MTB components work well here?

My guess the rest of the trace from the Garmin was the ambulance? I’m glad you came out OK.

– Richard

john - 11/24/13 - 2:41pm

ONCE AGAIN………

EPIC WEIGHT WEENIE FAIL OF THE YEAR.

HOW DOES IT FEEL TO BE A GUINEE PIG ?

40 LBS ALL MOUNTAIN , TOTALY SAFE.

IF YOU RIDE IN MOUNTAINS, SHOULDNT YOU BE RIDING A MOUNTAIN BIKE ?

ROAD OR OTHERWISE,.

BG - 01/31/14 - 6:03pm

Never nice to hear about someone crashing – hope you recovered OK.

My advice to anyone out there (and this would have been equally valid 2 years ago when this article was published) is to either go with Avid BB5 or BB7 brakes and use proper levers with cables. Or if you must have hydraulic calipers, buy the Hope V-Twin brakeset, and if you’re really paranoid about fluid boiling, swap the X2 calipers for V2 or V4. Hope use, of course, DOT 5.1 fluid which is one of your best defences against fluid boiling, along with big caliper pistons.

shane - 03/28/14 - 11:14am

As i found out in the automotive world, brake fluid cannot compress, so if you push your brake pedal and it goes to the floor, there is air in your lines from moisture that is boiling and this is telling you that you need to change your fluid more often. also i dont think riding the brakes down the hill was good, even in high performance automotive brakes, they are meant to brake very hard into a corner and then cool down, not have them slowly rubbing down a hill, There is a duty cycle that they are designed for. The same types of brake failures could probably also be seen in many vehicles going down the same road, even well maintained or newer vehicles.

Tracy - 06/24/14 - 1:07am

I think you need to maintain the disc brakes regularly for the safety of your and others too, there is not any fault of the manufacturer.

24tuccu - 08/01/14 - 7:00pm

if next time you find yourself with failing brakes (hopefully not) a foot gently pressured on top of the rear Tyre & just before the frame will slow you down to a stop!

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