Why Doesn’t Anyone Make a 29er Downhill Bike?

why doesn't anyone make a 29er downhill mountain bike by specialized banshee norco santa cruz niner and foes racing

After watching footage from the first few UCI World Cup downhill races this year, we’re sitting around the office blown away by the speed at which the riders could seemingly fling their bikes over some seriously gnarly roots, rocks and drops. We also noticed that some of the rocks and root “cavities” (the gullies between big roots) seemed to occasionally be just a hair too much for the bikes, forcing the riders to navigate around some obstacles rather than bomb over them.

Not being big downhillers here, we got to wondering why no one was running a 29″ wheel on a downhill mountain bike…at least on the front. As we all know by now, a 29er’s larger wheel rolls over stuff easier, and some of the bits on the World Cup downhill courses were seemingly just beyond the capability of a 26″ wheel to get over (even with 8″ of travel!), but could have been tackled by a 29er.

So, in typical Bikerumor fashion, we called the experts. Lots of them. We wanted input from big brands and small, global companies and boutique DH specialists. We also wanted a dedicated 29er brand…so we went overkill and interviewed the folks from Specialized, Foes, Banshee, Norco, Santa Cruz and Niner and asked them the following three questions:

  1. Why don’t downhillers use 29″ wheels, at least on the front?
  2. Has your company or any of it’s factory riders ever tested or prototyped a 29er or 69er downhill bike?
  3. Anything else you could add on this topic?

Hit ‘more’ to see how they answered (hint: Niner’s just might be working on something)…

This video, from the U.S. Open Downhill was the inspiration for this post.  The replies below definitely have some overlap, but we copied their responses in their entirety so you can pick up on any subtleties from your favorite brand(s).

1. Why don’t downhillers use 29″ wheels, at least on the front?

Brent Foes: That’s a good question, and common logic would indicate that the 29er would, indeed, be well worth developing as a downhiller platform. Interestingly, every few years designers in both the dirt motorcycling and bicycling industries fire up those lingering ideas about the benefits of larger wheels on rough ground. The latest of these is the 29″ wheel for mountain bikes. As you have suggested, dowhhillers could sure use the theoretical benefits – smaller friction coefficient – of a larger circumference wheel. However, as in all things wheel-oriented, there are real world sacrifices that have to be made for this gain – namely, the increased leverages and energies that downhill obstacles would place on the longer spokes – as well as on the rims and hubs. To mitigate this, we would, of course, have to make thicker gauge spokes and/or even heavier, flanged hubs, thicker rims and larger, thicker downhill tires than already exist. But, here’s the rub: a 29er wheel already has a greater rotating mass over the 26″ wheels currently built for downhill – add the mass of stronger spokes, rims, hubs and tires (and bigger brakes to control this mass) and you have an even larger sprung and rolling mass to contend with. Even in just the front, this would be much more difficult to control (steer, accelerate and brake) than the current setup.

Joe from Santa Cruz: Since the best downhill forks on the market are 26″ wheel specific, there is no option for a 29″ wheel on a DH bike that has the best in front suspension. Additionally, the increased height of the front end of the bike would cause issues, albeit surmountable if it was merely hand position. To the best of my knowledge, there are no DH tires or tubes for the wheel size either. Not “big knobby tires” but true DH casing, with tread profiles for different terrain and weather conditions. Or, for that matter, rims. For rear wheel travel, its difficult now to package tires, clearance and the amount of travel necessary, along with geometry that is good for DH racing with a 26″ wheel. Simply getting 8-10 inches of travel without the tire hitting the seat and a larger tire would prove difficult, and may cause major comprimises to other, arguably more important attributes.

Dustan from Norco: There are really two issues in marketing a downhill bike with 29″wheels:

1  They are inherently weaker than 26″
2  They increase the center of gravity significantly

Nic from Specialized: A 29″ wheel does make it easier to roll over obstacles vs. a 26″ wheel. In my experience, the gap begins to narrow as you get into longer suspension travel and slacker head angles. On short travel bikes, the wheel size difference and increased roll-over is more noticeable than a downhill bike with 180-200mm of fork travel and a 66 degree head angle. Also, larger wheels are not as strong which is not ideal for a DH bike. The trend in downhill is to get the front end of the bike as low as possible, and a 29″ front wheel combined with long travel will make it very hard to get the bars to a reasonable height, especially on a size small. 29″ rear wheels will pose an even greater problem, as it is very challenging to package 29″ and long travel into a reasonable setup with short chain stays. Saddle-tire interference at bottom-out is also an issue with the long travel and low saddle height of a downhill bike.

Jay from Banshee: Downhillers don’t use 29″ wheels for a couple big reasons and some are particle problems while others are performance based. First DH’s need travel and have found that 8″ front and back tend to be pretty decent numbers for absorbing big hits and chundery sections of trail – here’s where the problem comes in when designing a 29r DH bike. You physically can not have an 8″ travel DH bike without having an enormous wheelbase. Even now many longer travel 29rs feel like your driving a boat through tight and twisty sections, and this is a non starter for DH racers. Even at this moment Banshee is designing a 17.3″ chainstay 5″ travel 29r and the challenges to maintain those numbers are tremendous. Also even if you were to limit only the front to a 29r there is no fork on the market that will accommodate a 29r tire and give you 8″ of travel in a dual crown. Granted you could run less travel and still get the “feel” of 8″, but…

The big wheels are harder to get up to speed then a smaller tire and with any DH course I’ve ever raced or have seen there are slow tight sections followed by flat out sections. These sections are mixed throughout the race course and demand quick acceleration out of corners and fast starts right out of the gate. No DH racer is going to want a second slower start to get his bike up to speed and then have to gain it all back later. Now, one could argue then why not run 24″ front and back? While we played with this idea a few years back when the 24″ wheel was popular there were a few things that left us wanting. One was they didn’t carry their speed very well and I can personally remember barely making transitions on a couple runs where switching to a 26 it was no problem at all. I truly believe the 26″ tire is kind of a sweet spot for anything that is gravity driven.

Chris from Niner: A lot of the reason 29ers haven’t made it into the DH scene is the lack of available product for this market segment. There are really no tires or rims available, and very little in the way of long travel forks that can take DH punishment. We feel like there is still some viability here and are constantly pushing from our end to see some development of DH worthy parts. We’ll have an exclusive on a big hit tire to premier with our WFO 9 caller the WTB Kodiak. It’s a 2.5″ wide, burly big hit tire with tacky rubber and DNA for anti-pinch flatting. It’s not a true DH tire since it’s rolling on an Aramid bead to save weight, but it’s a very good compliment to a big hit 29er and can handle some DH use. We’ve tested the tire and the WFO 9 on DH courses across the country and it’s been very fun.

niner-wfo-milk-dud-29er

2. Has your company or any of it’s factory riders ever tested or prototyped a 29er or 69er downhill bike?

Niner: We’ve played around with our WFO 9 on the DH courses.  Earlier prototypes of the WFO 9 (which currently has 5.5″ of travel in the rear) featured as much as 6.5″ of travel and this is a LOT on a 29″ wheel.  We feel strongly that 29ers simply don’t need as much suspension travel as their 26″ wheel counterparts, so a viable DH rig can be built with less travel and therefore lighter weight.  Currently, even our production 5.5″ travel WFO 9 can handle DH (we offer a 150mm spacing on the rear and it has ISCG tabs for chain guides or a Hammerschmidt).

Specialized: We have never tested it, and Sam and Brendan have never requested or asked for any type of 29er or 69er Dh bike.  We are always willing to work with our riders and test their requests and suggestions, they have just never asked for it.

Norco: We do not have a 29″ downhill bike and you won’t likely see one in the next few years. The larger wheels have some benefits but the detriments unfortunately outweigh them. The idea of a 69er bike helps to keep the center of gravity lower than a 29er but also increases the stack height of the bar. The industry as a whole has worked quite hard to keep the bars/center of gravity low and this is moving in the wrong direction. At Norco we are looking at the 29er as an area of growth in the XC/AM markets but do not see an immediate need for a 29er DH bike.

Santa Cruz: No.

Banshee: We’ve never tested a 29r or 69r DH bike because no one has ever made one. The closest we are probably going to get is (a) bike we’re working on now. (Not the bike hinted at here, but Banshee’s Legend DH bike shown below)

banshee-legend-downhill-bike

Anything else you could add on this topic?

Banshee: I’m not sure if there is much to add with regards to a full DH 29r bike. The thing with these type of bikes is they do feel like you have more travel when you take a similar travel bike, say a 4″ in a 26, and put it up against the same travel 29r; the 29r is going to feel more like a 6″ travel when comparing the two. So this begs the question do we need an 8″ travel 29er or would a 6″ work just as well? For me DH falls into 2 categories, Freeride and DH race. The later I feel will always stick to 26″ but if winning isn’t your motivation and just having some fun then I think the 5″ to 6″ 29r will be the ticket, provided you can keep the jibbing/flickabilty aspect of the bike.

Specialized: Darren Berecloth rode the new 29r Stumpjumper yesterday and came back say good it felt and that he would like to try one up in BC, so who know maybe he will lead the charge to freeride 29ers.

Foes: When all is said and done, the 29er just doesn’t lend itself naturally to the requisite qualities of a current downhiller. The 26″ wheel in its present configuration seems to be the best compromise at the moment (and, this is why you only see shorter-travel 29ers). That is not to say that it will not be tried at some point – but, especially in these days of R & D cutbacks, it’s difficult to make the case for a clean-sheet design to achieve a minimum (if any at all) gain in just one small part of the downhill equation.

Niner: We think 29ers can be competitive on the DH scene, and are pushing for manufactures to believe in longer travel components for 29ers.  We think it’s only a matter of time before this can become a reality.

Santa Cruz: 29er advocates appear to have set the benchmark of 29er acceptance as the wheel size being applied to DH bikes. Unfortunately, I have met no advocates that understand well the rigors and abuse that World Cup racers put frames through, and demand from their machines. Many of these issues have yet to be resolved entirely for 26 inch wheels, and the DH market is very small. For example, there is only one rain race tire used by the entire pro field – because other companies refuse to tool parts for such a small market. Look at the cost of a Fox 40 or Boxxer World cup fork. Those are platforms that are specifically designed for the 26 inch wheel, and are very expensive to develop. Segmenting the DH market further is likely to be a major hurdle.

2010-specialized-demo-8-downhill

Editor’s note: Just for fun, here’s Specialized’s 2010 Demo 8 downhill bike…full post on the 2010 Specialized mountain bikes coming up this week…

Comments

Guitar Ted - 07/14/09 - 12:22am

Well, this is interesting stuff. My opinion? DH and 29″ers are not where it will go. However; that said, six inch travel 29″ers already exist (Lenz Lunchbox) with sub 18 inch chainstays. Also, I am aware of an 8 inch travel design, but the designer is waiting for the forks and tires to become available that will match up to this style of bike. Once the parts are in place, the bike is going to be made.

Six inches I think will be about the limit for production companies and I think it will be the extreme limit for what folks will accept in terms of weight, strength, and sizing limitations.

While DH is cool, exciting, and the tech behind it is geek-o-riffic, I really do not think 29 inch wheels will go there, nor do I think that we need DH 29″ers to make the wagon wheelers “valid”. Come to think of it, 26″ers didn’t need DH to validate that size either.

Great post, thanks!

Walt - 07/14/09 - 9:04am

Er, both Alex at BCD and myself have been making 29″ wheel DH bikes for years. My personal bike is 7/8″ travel, 17″ chainstays, and a very reasonable bar height. It’s also under 40 pounds without any particularly fancy parts.

Yes, tires and rims are a problem, but that will eventually sort itself out. 29ers won’t ever be a huge part of the DH *racing* scene, but the vast majority of lift-served riders don’t race and could potentially benefit.

Next time you do an article like this, do some real research – you could have had Alex or I (people who have actually both built and ridden DH 29ers) kick in some real-world answers.

-Walt

hackblaw - 07/14/09 - 9:19am

OMG NEW DEMO
8!!!!!!

Shkenblke - 07/14/09 - 1:12pm

Did any one ever consider maybe a 650b DH option?

29er rider - 07/16/09 - 11:43am

Definitely Walt and BCD knocked the nail on the head. You anyone makes a real exstimation and tests we need 7″ 29ers to be done on broad scale by those manufacturers above. The most accurate coments are form Niner owing to their longer travel inroads. The vialibility of words are accessed by real world experiences not flourishing fantasy.
Others are like commenting on disc brakes and suspension in 80-ties- telling us about the power loss and hoses, which constantly spewing the fluid. Santa summed up their experience with longer travel 29ers with “NO”.

[...] We’re surprised as heck to see it given Santa Cruz’s comments on our 29er DH post and on their engineering guy’s own blog, [...]

Mike The Bike - 08/01/09 - 5:23pm

Oh Thanks! I was waiting for this question for an age! If you want real players in this matter maybe you’ve got to knock the door at NICOLAI (Germany), MICHELIN (France) and BOSS (France again) to get a full package and get rid of any excuses (maybe you can add a ROHLOFF 14 HUB (Germany again) to avoid broken derrailleurs. We need real ingeniering (= Germany )

Richard - 08/09/09 - 2:17am

I’d seen the 24 inch back and 26 inch front DH bike a few years back. My vision of a future DH bike would be 26 inch wheel in the back with 8 inch travel suspension and shimano Nexus 8 speed gear hub. The front wheel will have 28 inch with 7 inch travel fork. The 29r is just overkill for DH bike. I don’t understand why 28 inch wheel has never been considered. 650b or 27.5 inch wheel doesn’t make sense at all.

DHracer - 08/24/09 - 9:57pm

Mike… clearly you don’t race downhill. Rohloff will add a ton of unsprung mass to your wheels and add pounds to your bike… so if you want to go slower put on a Rohloff or a gearboxx.
As for engineering last i checked Germany still hadn’t put a man in space, and France still hasthe Airbus, Italians have Ferrari, and the Japanese slay in anything electronic, so if the best they can engineer is a couple of cars I wouldn’t be running around thinking Germany is THE end all be all when it comes to engineering stuff. Just because you drill a million holes in your frame doesn’t mean you can engineer a frame better.

[...] Interview: Why Doesn’t Anyone Make a 29er Downhill Mountain Bike? [...]

Todd - 03/04/10 - 11:39pm

I have been messing around with a 29′er on my DH race bike for a little over a year now. Its nothing new for sure. The problem is tire choice. WTB is the only company that I can find that is making anything wide enough and its still a folding tire. Also I dont have any DH buddies that run presta tubes. All I can find are thin wall presta tubes. I run my 26 when the rocks get to bad.

lol - 06/21/10 - 2:37am

HAHAHAHA Nicholai mike? Seriously? Hate to say it but Nicholai frames are waaaaaaaaaaaaaaay over priced, outdated, over gusseted and just plain un needed frames. They have pioneered squat also.

Funny people are going after specialized knowledge in things… especially when they have pioneered many things in MTB. Santa Cruz and Banshee are also on the top of the world cup circuit. I think you guys questing these companies this site interviewed needs to realize who is on top in the world standings. These companies. Don’t you guys think they know a thing or two about bikes… especially if their bikes make it to the top of the podiums in the top of the pro ranks on a consistent yearly basis. Point being…. 29 er bikes are just not strong like said. I also don’t see the guys from BCD hucking cliffs, shredding whistler etc. They are dedicated race bikes at bcd, not bash the shit out of on a daily basis and still ride bikes.

JM - 08/05/10 - 2:25pm

At the end of the day DH world cup racers…if a 29er DH bike gets them from A to B faster…they will ride em end of story? It’s all about time and wins

[...] photos while on a tour of the Trek factory…looks like that whole 29er downhill bike thing we explored a while bike is getting some play by the big boys. They also hinted at (in code, no less) that a redesigned [...]

Cloxxki - 02/28/11 - 5:29am

It never fails to amaze me how clueless the big shots at bike brands can be. Niner the main exception here, they’ve come a long way, but always had the 29″ spirit of course.

Same argument as with 7″ and 8″ disk brake rotors. Every year, manufacturs claim double digit percentage power improvements, yet after 15 years of so, XC still requires 6″, DH 8″.
So after 35 years of DH bike, a 2.5″ larger (10%) rim still can’t take the abuse, the spokes are still too long to be stiff enough? yeah right. Wheel performance SEEMS restricted by rim diameter, due to hub width having been fixed for so long, and 32 spoke having taken over from the (road bike) standard of 36 spoke. 99.5% of all MTB’s with disk brakes still have the same front hub width as a 1960′s (guessing here) road bike, which had 4 spokes more to boot. Yet road bike can now have proper wheels with half as many spokes. Did road riders become more delicate to their equipment? Must be.

These clueless bike brands are our idols. We long for their new brochures to learn about the latest best technologies and trends. Again, Niner the welcome exception.
I used to work with Banshee. Many years ago, they were ready to make me a 29″er. I was working on getting a tire made, a rim made, and already had the fork (WhiteBros agreed to supply it to spec).
The very thing that got 29″ to exist, GUTS from WTB, is lacking with the rest of the Industry. Again except for Niner, who started a 29″ brand when there was barely a market for it. No-one was asking for a Scandium Singlespeed-specific EBB 29″er.
That no-one’s asking for a miracle doesn’t mean no-one would benefit from one, or would pull their wallet to get in on the action.

As Banchee and Niner indicate, a 29″ DH bike (wheel will measure 30″ across), will not NEED the typical amount of travel as found on a 26″ bike. It will be less useful for vertical drops for all the obvious reasons, but will outperform the kiddywheels at every single moment the axles are turning. Those who think 29″ has a disadvantage in corners, never shared a singletrack with a capable 29″ rider. Those who think acceleration is an issue, fail to see that beside the wheels, there’s about 100kg of other mass to be dragged along. And as speed increases, so does the rolling resistance advantage. Being an XC racer (starts from dead stop, with 10-20 guys trying to beat you to the first corner) I know 29″ers just rock for accelerations. There’s so much more to it that wheel weight.

Bikes are smalltime bizz, that’s why brands get away with spreading nonsense. Once one brand manages a capable WC DH winner bike, and finds a worthy rider prepared to merely give it a go, the whole DH markt will increase by some 10%, in absolute size :-)

dogs dinner - 04/16/11 - 6:07pm

I would like to see a full sus with 29front and 24rear, just for the hell of it, absolutely useless for competition, but it could look kinda cool, and going downhill, in a really straight line, on a really steep descent, it could be fun!! Could work nicely for chucking if the weakness issues were addressed.
if anyone out there has done this, and has pictures, post a link! : )

Rob - 04/03/12 - 9:25pm

it’s not Rocket science is it ?
take a look at Dirt Bikes ?!
larger diameter front, rolls easier, and easier steering.
on the back need a fat tire, with higher volume ,
since the rear will hit , whatever the front got over.
make the rear at least 50mm (60mm) beefed up doublewall rim, with a 3.0 tire,
a 24″ would make sense, to keep the chainstay short.
front also fat rim, 45-55mm .
but tire availability is slim, for 24″ , 29″,
and for handlebar, on a dual crown fork, should be able to put it lower , if needed.
while we are at, might as well, have dual front discs , so you don’t cook the oil on the ski slope.
oh, did I mention tubeless ? for now glue it, or use tubes with baby powder ,…

Doorgunner - 08/04/12 - 2:20pm

Most of the arguments against a DH 29er look pretty weak to me. That there aren’t a lot of parts for it, or that they are or would be expensive is, of course, irrelevant. That riders haven’t asked for it (Specialized) is the lamest excuse for not thinking I’ve ever heard. The rest of it all looks like excuses to me. Sure there are problems, but none of them individually or collectively obviously outweigh the benefits – which I think would be substantial. Someone should at least try it, instead of churning out the same old stuff every year.

This looks to me more like the industry is stuck in it’s ways and not forward-thinking. I am old enough to remember when all the same sort of negative arguments were used against the idea of having any kind of suspension on a bike.

Chevalier Bleu - 01/18/13 - 5:17am

Center of Gravity is indeed an issue. For DH there are lots of speedy corners, leanings and jumping. For the 1st 2 issues, larger tires means more difficult to control without increasing the width of tire, thus makes additional weight. Wider tires (more and larger knobs required) as everyone knows it will need more power to drive. In marketing point of view, new products are developed for more efficient. Everyone (DH racers and spectators) wants to see faster bikes running up, and down…
Then for jumping it is indeed something more technical and I don’t wanna repeat what Brent said.
I personally feel 29er looks weird and don’t want that happen on a DH bike and that’s why I am here.

massy newmy - 05/10/13 - 7:02pm

It is so hilarious to read this article in 2013…………………………So much has changed

Josh - 06/04/13 - 5:07pm

Cloxxki, are you listening to yourself. “Yet road bike[SIC] can now have proper wheels with half as many spokes.” Yes, because they are on a flat surface. Then you finish off with saying, “Being a XC racer… I know 29″ers just rock for accelerations.” You obviously are a XC rider. The whole point of what all these people are saying is that the wheels are too weak, needing bigger rims and spokes, making the bike to be heavier, thus, losing stability, and in return, causing the wheel to be heavier, making it harder for acceleration. Plus, 29ers do not have neither as well handling nor stability, which are needed for tight turns and jumps. And downhill mountain biking consists of many tight turns and jumps.

Although, there are some advantages to 29ers, which the UCI World Cup downhill racers do not need. 29ers are faster and keep speed better on flatter flatter grounds. But, there are not many flat grounds where this would make up for all the disadvantages. Secondly, they ride smoother, which these riders do not care about, they care about how to get from point A to point B the fastest.

And lastly, would these riders use 26ers if 29ers are a better option. These riders would ride the fastest bikes that they are able to ride, not because they feel like it.

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