Five Questions: WTB's Jason Moeschler on Wheel and Tire Design

Jason Moeschler came to WTB with a classic bike industry resume and a passion for perfection. Eleven years on the ground floor working at a bike shop, one Junior National Championship XC title, and three trips to the XC Worlds provided him with an enviable education. Three Downieville All-Mountain Pro victories illustrate that the man can walk the walk and talk the talk when the topic is about trailbike performance. Presently, Jason is WTB's Manager of Global OEM sales, but WTB is a compact operation and everyone there wears more than one hat. One of his tasks is to shepherd the development tires and wheels from concepts through final production. Jason explains his position as:

---

The present tire and rim standards seem antiquated to me. Riders have been wrestling with the same issues with clincher tires for over a hundred years. For example, DH racing is pretty much hobbled by the fact that tire and rim makers can’t seem to figure out how to make a wheel that can function for less than six minutes on a World Cup course. By contrast, Supercross racers often race and podium on flat tires. What is missing from this equation?

Supercross riders have motors. It doesn't matter how heavy their tire and wheel setup is, because they have motors to overcome any weight gain. So yes, they can make the tire as heavy and durable as they need. As long as the tire stays seated, they are fine. Mountain bikers have power output (watts per kilogram of body and bike weight) and that is it. Mountain Bikers don’t have the luxury of making product as heavy and tough as we want, because we have to pedal. Downhill happens to land as this odd category in the middle of Moto and good old mountain biking. I am not a downhill racer, but from what I have seen, the top riders are always cutting corners, using the lightest product possible in an effort to gain an advantage. In other words, they are using product outside of its intended use.

In terms of the rims and tires that I ride, race, and develop, things have improved massive amounts in the past 15 years. Example: WTB used to host a distributor launch in Downieville. The Downieville DH is notorious for flat tires, and before current technologies, our guests at the distributor camp would spend as much time fixing flats as riding. Flats would come in the form of pinch flats, tires coming de-beaded, or cuts to the casing. We would have to carry beer on the ride to keep spirits up. This was a problem for all tire makers. Fast-forward to the last Shimano XTR product launch, also held in the Downieville area. The bikes were fitted with WTB TCS tubeless tries, Shimano XTR tubeless wheels, and tire sealant. We had a much larger group participating in the Shimano camp, spanning more days. We only experienced one flat. Call me crazy, but I would say this example proves huge improvement.

Yes, there is still room to get better. However, if you use a proper tubeless set up, the vast majority of flats are eliminated. You think Weir, Cruz, Osborne, Riddle, Sternberg, Price or I ride around, being worried about flatting or burping tires? Heck no!

The big issue for mountain bikes these days is tire and rim compatibility. How do you ensure that your tire and rim are compatible? Will your tire install easy, or will it be a total nightmare. Will you be able to inflate the tire, or will air and sealant leak out all over the place? Will the tire seat at a reasonable pressure, or do you need 100psi to get the tire properly seated? Is the tire going to blow off the rim because it fits too tight? The fact that the consumer has to worry about these issues on a daily basis is crazy. What is really crazy is that the consumer accepts these issues as normal. Sorry, but I won’t be caught dead riding a tire/rim combo that has the potential of the tire burping, or coming de-beaded. I shake my head every time I see an accident related to a tire coming off a rim. Lars Sternberg flatted in two separate EWS races this season, and was able to ride down the track without unseating his tire. Why? Because his rim and tire meet ETRTO tubeless standards.



"Tubeless-ready." What exactly does this term mean? Tubeless ready is not a standard. There is no manual that explains the exact specifications of tubeless-ready tire and rim fit. Thus, you get many tubeless-ready products that don’t seem to fit together very well. The key to proper tire and rim fit is the ETRTO (European Tire and Rim Trade Organization) manual. This is the same manual that dictates tire and rim fit for Supercross bikes mentioned above, or the cars that we drive every day. I guarantee there are no car makers that are ok with tires and rims that can peel apart during use. But guess what? The ETRTO manual includes a specification for Bicycle Tubeless. If the mountain bike tire and rim are made to the ETRTO tubeless specifications, the tire and rim will fit together well, inflate and seat easily, and stay secure while riding, even when flat. WTB product follows ETRTO, and we get great results. We don’t have our own system. We are simply following the industry standards. Our product works really well with other brands of product that follow ETRTO. And guess what? Our product might not work so well with brands that don’t follow the INDUSTRY STANDARDS. Who is to blame here?

What is your stance on wide rims. What are the benefits and what are the drawbacks?

We are currently testing a few different widths of rim, both much wider than current industry standard, 19mm to 25mm inner width. We like the performance of the tire casing on the wider rims. The tire feels completely different, in a good way. The big drawback is weight. Do you really want to add weight to the outside of your wheel? Carbon helps solve the weight issue, but then the question comes: Do you want to spend the money for carbon rims? Another drawback we have found is that current tire profiles need to be re-worked. Current tire profiles aren't designed to be used on rims over 27mm wide. The result is a very square profile to the tread.



WTB’s new mid-sized 27.5 Fat-bike wheel and tire represent the first out-of-the-box development that your team has developed in that area of your business since I can remember. As I understand it, the lion’s share of WTB’s revenues come from its OEM customers, which are bound to follow strict international standards or face expensive legal liabilities. Could that be the motivating factor that keeps WTB’s wheel and tire development marching on the conservative side of the ETRTO standards?

Thanks for the slice of humble pie RC. I can always count on you to wake people up with a good old bitch slap. I have been breaking my back (literally) to make sure that WTB falls back into place as an innovator. I entered WTB during a very bad time in the company’s history. Product development decisions where in the hands of individuals not qualified to handle the task. That issue has been solved, and now you can hopefully see a new breath of life when you look at WTB. I wish I could show you some of the stuff we are working on. Even you would be proud and excited.

As mentioned above, I don’t think ETRTO tubeless standards are conservative. When practiced properly, ETRTO Tubeless standards are the only way to keep a tire on Weirs bike. It’s that simple. I believe the diversion from ETRTO is the cause for the lion’s share of tire and rim issues faced today. Yes, 27.5+ is not an ETRTO regulated size. Yes, 27.5+ is out of the box. However, our design of the tire and rim still follows ETRTO principals to ensure proper tire and rim fit and retention.

You actually have it wrong regarding OEM’s following ETRTO standards. Most OEM’s don’t pay attention to ETRTO. They don’t think it is an issue, and I have really had to back down on how aggressive I am with the ETRTO conversation. I know what happens when things go wrong, and lawyers get involved. No one in our industry wants to be in court over tire and rim fit issues.

WTB has been a great supporter of aluminum vs. carbon for making rims. Now WTB is ready to launch its first carbon mountain bike rims and wheelsets. What changed everyone’s mind and in what ways does the new rim differ from other makes that would validate that decision?

WTB has been testing carbon rims for a long time. We have broken thousands and thousands of dollars worth of carbon rims. It is undeniable that carbon rims ride better than aluminum. It is also undeniable how many carbon rims one can see broken on any given race weekend, especially when the race track has rock. Refer to my statement regarding DH racers cutting corners to gain any advantage they can. Carbon rims give the rider an advantage. They are lighter and stiffer, and allow for better acceleration. Carbon hoops make the whole bike feel better - until you bottom the rim out on a rock, and the rim explodes.



I have recently lightened my personal stance on carbon rims. There is a time and a place where carbon rims are the best tool in the toolbox. When I (not WTB) originally came out against carbon, it was because our testers were getting pissed. You break a carbon rim, and your ride is likely over. Marco Osborne just demonstrated this in the Oregon Enduro finals up in Hood River. Strike an aluminum rim on a rock and it is usually no big deal. The aluminum dents, and you keep on riding. The lesson? There is a time and a place for Carbon rims.

I wish I could say that the WTB Carbon rims are light years better than the competition. The simple fact is, if you get a big enough guy and hit the rim hard on a rock, he might end up with a broken rim. This big guy might want to choose aluminum instead. What I can say is, that our carbon rims exceed CEN impact tests, we have the most rad spoke nipple seat ever, our layup and resin content is completely unique, and the rim is ETRTO tubeless. All admirable traits that make for a really nice riding, and exceptionally durable wheel. Now I’m being a sales guy. The truth: We had to make our carbon rims tough enough to withstand Weir, Cruz and Osborne, and some other gnarly guys. These riders are what pushed us to develop the new types of layup, and play with resin content. Are they unbreakable? No. Are they really strong? Yes. Better than the competition? Yes. Stronger than aluminum? No. Sexier than aluminum? Absolutely.



Trek has introduced a wider hub standard and we are already seeing a shift towards wider rims. Those seem like improvements, however, not innovations. Where do you envision the next big improvement in wheel technology will come from?

The wide hub standard does help to make the wheel more stiff, which is an improvement with the cost of increasing Q factor. You could use an asymmetric rim, and achieve a similar feel to the wheel without adding Q factor. Wide rims address stiffness at the tire and rim. When using a wider rim, the difference in tire feel is profound. The tire feels much more rigid, and there is less tire fold in the corners. However, there is a weight penalty with wide rims. I think the first step in wheel technology improvement will be for the bike industry as a whole to align itself with tire and rim fit. You would be surprised how much tire and rim performance would improve if the fit between tire and rims were standardized. From there, we can look beyond to the next step, with improved tire and rim materials, to further reduce weight and add strength.

---

MENTIONS: @WTB-Bikes, @trek

---

Posted In:
Interviews WTB