Curtis Keene is a big, strong, wheel crushing freak of a man. His mountain bike resumé includes years of World Cup downhill racing, EWS enduro competition, and thousands upon thousands of hours finding the limits of a mountain bike’s capacity for abuse in and around his rocky, ledgy, Southern California home turf. His formidable riding skillset and penchant for finding the failure point in most products dovetails perfectly with Roval’s field testing program; a crucial step in our product development process. It is here, in real-world conditions, that we determine the final validity of a wheel’s performance.
This is a long journey. From an initial idea or concept, a wheel first gets rapidly developed via computer modeling. The increasing sophistication of Finite Element Analysis, along with our own constantly expanding database of knowledge, allows us to immediately dismiss unworkable concepts and focus on designs that will meet our desired strength, weight, and ride characteristic targets. With computer modeling, we can hone in on materials and near-final shape, as well as conduct extensive theoretical stress testing. This eliminates a huge amount of guesswork but is still a totally virtual phase of wheel development. From there, we move on to prototyping and lab testing. This can get a little Sisyphean, moving from one prototype iteration through a wide range of destructive testing before heading back to the drawing board and tweaking the design to improve the next prototype and test it all over again. And again. And on… During this phase of the design on the Control SL, for example, we went through SIXTEEN different rim shapes before we got the shape and characteristics we wanted. Finally, after all that building, destruction, and building again, we are ready to head into the real world for further testing, where we introduce the wheels to Curtis and his friends.
Jeff Meyer, Roval’s engineering manager, describes the need for field testing: “Our lab tests are robust and represent the majority of riding, but riding styles and trends are always changing. So field testing allows us to identify how new riding styles are loading wheels. If we see a new failure-mode in the field, then we need to find a way to replicate it in the lab. Once we accurately replicate the failure mode in the lab, then we further understand by learning how to turn the failure on/off with design changes. It comes full circle when we field test improved product without failure.”
In addition to the dynamic of evolving riding styles and changeable terrain, field testing also introduces more variables than might be encountered in the controlled environment of lab testing. “Riding is also much less controlled than lab testing, and it’s also a lot dirtier - read: contamination,” Jeff continues. “So we have to include field testing in all product development. The trick is getting the right riders who are going to put on sufficient hours in the right terrain.”
The right riders and the right terrain is a very broad brush to paint with, though, when it comes to mountain bike wheels. We look for answers in three areas with field testing: Ride dynamic, single event durability, and long-term durability. Ride dynamic asks how the wheel “feels” – does it improve handling, control, comfort? Long-term durability investigates real-world reliability – can the wheel survive extended use in a wide variety of environments? How easy is it to live with, what is the best possible user satisfaction over the long-term? For much of ride dynamic and long-term testing, we pull data from a wide range of rider skill levels, riding styles, and locales. This is necessary in order to get a full picture of how the wheel works. What might be a perfect wheel for a pro racer may not feel so great for a lower-wattage recreational rider.
Single event durability, well, that’s the graveyard scenario. Can the wheel survive unexpected harsh impacts? What events cause the most severe loading, and what is the failure mode? This is where it’s a mighty good thing to have a 190-pound former DH Pro wrecking ball in your back pocket. Curtis Keene spends up to 15 hours a week riding hard and fast, pushing himself and our products to their limits. His feedback is one invaluable stream of information coming in from a diverse group of testers.
Curtis’s seat of the pants intuition is compared to the information gleaned from onboard data acquisition devices. “These allow us to quantify rider’s qualitative feedback,” says Jeff. “This first lets us understand what is happening in the field, then it allows us to quantitatively compare wheel/tire systems. So we consider rider feedback, rider survey data, accelerometer data, and known wheel characteristics – like stiffness. The surveys are designed to turn the rider’s subjective impressions into quantified feedback. Anyway, all of this allows us to understand riding styles and trends, the resulting wheel/bike loading, and how wheels affect performance and perception.”
“We have a wide variety of customers and riders, so we select test riders who will help us understand each of those groups. Riders like Curtis will load the wheels in a completely different way from our typical customer since he is big, strong, and fast,” Jeff concludes. If the wheels survive his abuse, if he is satisfied with their performance, then we are confident that they will endure the hardest riders and the harshest conditions. That’s one part of the puzzle we can lock into place as we continue to evolve our mountain bike wheels, always looking for new ways to improve everyone’s ride.