First up, I had a nice long conversation Friday morning with Stan, the founder of NoTubes, with the intent of just seeing what was up with their lawsuit against Specialized. Ã‚Â I’ve updated that post with the juicy tidbits, including a buyout option that fell through…read it if you like industry gossip.
The phone call quickly went from what Specialized was copying to what makes Stan’s wheels and tires so unique and why so many of the Pros seem to be racing his wheels (Dave Weins and Lance Armstrong used them to take 1-2 in the Leadville 100…and that pic of Lance racing a Fisher 29er? Ã‚Â Those are the new 7000 series NoTubes wheels.)
This isn’t exactly an apples-to-apples comparison because of the angles, but the slight difference…we’re talking 2-3mm…in inside rim height where the tire seats against the rim wall is what makes the difference in Stan’s NoTubes wheels. Ã‚Â Stan is one passionate man when it comes to talking wheels. Ã‚Â It’s infectious, and you can read why this tiny little difference will make you about 1mph faster on the trail, just click “more“…
WEIGHTS AND PRICING
The picture above also shows a subtle but important difference in the shape of the rim bead. Ã‚Â With Stan’s, it’s slightly less pronounced, what they call a “bead socket”. Ã‚Â By reducing the amount of material used for a bead and for a tall sidewall, they can more more material to the center of the rim to improve stiffness and strength, while still making a rim that’s about 20g to 40g lighter than a comparable Mavic. Ã‚Â
The Stan’s ZTR 355 Disc wheel weighs in between 350g and 380g for a 32 hole drill pattern. Ã‚Â They MSRP at $75, 29er/650b rims are $85.
Then it gets even lighter! Ã‚Â Their new ZTR Race 7000 Series rim that’s only 284g! Ã‚Â This rim is only available as part of their 7000 Series Race Wheelset (shown above, click to enlarge), but the entire wheelset, using Custom Black DT Revolution 1.8/1.5 spokes and American Classic Disc 130/225 hubs, weighs just 1210 grams! Ã‚Â The best part? Ã‚Â They’re priced at just $950.
For comparison, the new Bontrager XXX Lite carbon-rimmed wheelset weighs 1490g and costs $2,000. Ã‚Â Mavic’s CrossMax SLR Disc weighs 1520g and has an MSRP around $1,200.
BENEFITS OF THE DESIGN
Here is where the conversation turned technical.
So, what are the benefits of a shorter sidewall? Ã‚Â They are many:
1. Less weight, which means less rolling resistance. Ã‚Â But, it saves weight in more ways than one. Ã‚Â Besides using less material in a taller sidewall, they can use less material strengthening the sidewall. Ã‚Â Why? Ã‚Â Physics. Ã‚Â Imagine the air pressure and lateral forces of the tire pushing against the inside of the rim wall. Ã‚Â A taller wall needs to be stronger to resist those forces, which means more material. Ã‚Â Stan’s shorter walls don’t need as much extra material to reinforce the sidewalls, which lets them put a little more in the center of the rim to keep it stiff…and it still comes out lighter than competitors’ wheels.
2. It makes the tire more stable. Ã‚Â Imagine the inside of a typical wheel where the tire bead has more room to sit below the rim’s bead. Ã‚Â As you inflate it, the tire bead sits flush against the sidewall and below the rim bead. Ã‚Â This forces the tire’s sidewall to bend inward first, then outward. Ã‚Â According to Stan, this predisposes the tire to shift to one side when entering a turn, meaning you lose a little traction at first while the tire settles into position. Ã‚Â See below for a crude rendering of this concept:
The wheel on LEFT shows how a lower sidewall and less intrusive rim bead keeps the sidewall of the tire in a better position. Ã‚Â On the RIGHT is a more traditional wheel where the sidewall of the tire is forced to bend around the bead first.
3. Widens the stance of the tire. Ã‚Â Stan claims his 24.4mm rim width gives the tire just as much stability as a traditional 30mm rim. Ã‚Â This also helps to decreases the amount of lateral distortion the tire experiences as you enter a corner.
4. Reduces pinch flats. Ã‚Â Here’s where my crude drawing above doesn’t do this concept justice. Ã‚Â Imagine that you hit a big rock and your tire compresses hard. Ã‚Â In a typical wheel, the tire is going to squish against the rim and you have a good chance of pinch flatting. Ã‚Â With Stan’s set up, the top part of the tire’s kevlar bead actually sits just above the rim profile. Ã‚Â This way, when your tire compresses down, it compresses into and with the kevlar bead, giving your tire extra cushion, dramatically decreasing the likelihood of a pinch flat.
5. Lets you run tire pressures as low as 15 PSI.
Here are what a couple of pros are running, according to Stan:
- Geoff Kabush (165 lbs) – 20 psi front / 23 psi rear
- Mary McConneloug (110 lbs) – 15.5 psi front / 18.5 psi rear
Why in the world would you want to run your tires that low? Ã‚Â Good question, let’s ask Stan.
“When you run lower tire pressure, you reduce Rebound Force. Ã‚Â Rebound Force is what pushes your wheel up and back when it hits an obstacle. Ã‚Â We’ve tested our wheels and tires on a 3/4″ bump at 20psi and 40psi. Ã‚Â At 20psi, your tire conforms around the bump rather than rebounding, and we’ve calculated about a 1/2 to 3/4 MPH improvement.”
Basically, the tire “mushes” around the obstacle rather than bouncing off it. Ã‚Â I’ve always thought this “mushiness” equaled lower rolling resistance, but Stan swears a rider on his tires (more on that in a minute) running about 20 psi could keep up equally as efficiently as someone on slicks at 70psi.
Another benefit is the “suspension” you get out of the tires. Ã‚Â This lets you run shorter suspension, which, depending on the bike’s setup, could equate to better efficiency, too.
What else? Better Traction. Ã‚Â And with better traction, you can change tires to a much, much lower tread profile…case in point, Stan’s Crow Tire:
Dave and Lance used the Crow during the Leadville 100 this year.
Stan claims the combination of low tire pressure and his tires’ low tread profile equals dramatically improved efficiency. Ã‚Â Here’s how:
1. With lower tire pressure, the tire conforms better to the ground. Seems obvious. Ã‚Â But what happens when you have a big knobby tire that’s trying to conform to the ground? Ã‚Â Big knobs that are mushing around without adding a lot of traction. Ã‚Â Stan compared this to crawling with fingers rather than grabbing with a full hand for traction. Ã‚Â What ends up happening with taller knobs is a lot of energy is wasted moving the knobs rather than moving you.
2. Better cornering traction. Ã‚Â Lower knobs means less distortion around a corner since there are no knobs to bend before the tire settles into what it’s supposed to be doing.
3. Better aerodynamics. Ã‚Â Tall knobs catch air. Ã‚Â Doesn’t sound like much, but in race circumstances, every little bit counts.
4. Tread compound increases forward movement. Ã‚Â With Stan’s tires, which are made by Kenda, they use a dual tread compound. Ã‚Â This puts a firmer rubber in the center and softer rubber on the sides. Ã‚Â This not only improves cornering and forward momentum, but helps the tires last longer…to the tune of about 1,000 miles per tire.
5. Lower knobs means less rotational mass, which means you can pedal them up to speed quicker and easier, and they’ll roll much more efficiently, too.
For those that aren’t comfortable with such a low knob, the Raven (above) offers ever so slightly taller knobs, especially on the sidewall. Ã‚Â Both tires are non-directional and can be run front or rear, and like Kenda’s tires, they’re a bargain. Ã‚Â $40 MSRP for 26″ tires and $45 for 29er.
PUTTING IT ALL TOGETHER
As I re-read this post before publishing it, I reads like a trainwreck of information, barreling along from topic to topic…which is sort of what the phone conversation with Stan was like (in a good way). Ã‚Â He summed it up nicely by saying this:
“There are so many little things people don’t think of that add up to real performance gains, and we’ve tried to incorporate all of them in our wheel and tire systems.”
Let’s assume the lightweight and low rolling resistance of the tire design add another 1/4 MPH to your top end, which is entirely reasonable, giving you a total advantage of 1 MPH by using Stan’s wheelset/tire system. Ã‚Â Adding 1 MPH is a substantial gain. Ã‚Â I remember looking at race results from my XC days and seeing the person in front of me having a 0.1 MPH difference, but it translated to a gap of several minutes during a typical race.
Even if you don’t necessarily buy into Stan’s philosophies, it’s hard to beat the fact that a) pros are winning on his wheels, b) they cost less than other high end models and c) they’re lighter.
SO WHAT’S NEXT?
Stan says he’s already applying lessons learned from the 7000 series to develop an even better wheel, and he’s tinkering with a hub design. Ã‚Â Right now, all of his wheels are built using either DT or Wheelsmith spokes and Hope, Cannondale Lefty, American Classic or WTB hubs.
If you’re wondering, all of the wheels that he puts under the pros use the American Classic hubs…and there are a lot of pros using them to win World Championships and other top races. Ã‚Â American and Canadian XC racers used them for the Olympics.