The new Roval Control SL wheels just landed, and they represent the distillation of everything we know about wheels into a potent, paradigm shifting, weapons-grade, podium seeking XC wheelset. We talked about rim design in this previous blog post, and want to spend some time now going a little deeper with the hubs. These aren’t just some random, off-the-shelf components. Chuck Texeira, one of the industry’s most accomplished engineers and the lead on the Control SL project, will talk us through.
“We partnered with DT Swiss on the development of the Control SL hubs; prototyped them in house – machined up some super light hubs that helped our prototype wheels weigh under 1200g, and that’s what led us into the design that we took to DT,” Chuck explains, before getting into the details that make these hubs special.
Weight reduction was a huge goal. Chuck describes some of the methods employed to pare the grams down so low: “We were able to achieve some big weight savings with the front hub by basically eliminating the front axle. That had a cascading effect in that it allowed us to then use a smaller diameter bearing, and THAT allowed us to make a smaller hub shell. The entire front hub assembly weighs the same as the preceding generation Control hub SHELL. This is exactly how old 20mm thru axle hubs work, and this is basically an adaptation of that thinking. We’ve had zero problems with this design, even after rigorous testing.”
From a minimalist hub design, care was then taken to achieve maximum strength with minimum weight between the hub and the rim, via the spokes. “It’s a low spoke count wheel, and using super thin spokes,” says Chuck. “The spokes are bladed T-head spokes, mating into T-head holes in the hub. This way, the bladed spokes won’t spin at the hub end when the spokes are being tensioned, or when the wheel is being flexed or loaded.” This ensures that the spokes stay aligned in their correct direction, and reduces friction and stress between spokes, hub and rim.
Being able to design the hubs and rims together, we were able to realize gains in strength while reducing weight, along with some convenient functional enhancements. Chuck explains: “These wheels use the same length spokes on both drive and non-drive sides, and front and rear. In order to achieve equal length spokes, we had to be very careful about where we placed the hub flanges, how we drilled them – you’ll notice variation in the depth of the holes drilled in the hubs where the t-heads sit.”
Describing the process required to drill the hubs with the different depths required for this unique application, Chuck details the process and some of the advantages it yields. “We had to design the hubshell with enough room to be able to drill the holes that way. But we were also able to maximize the spoke bracing angle, and also get the spokes entering the rim at the exact right angle.”
All this ensures that the wheel is designed and built as a system, with each component working in harmony with the others. Additionally, DT Swiss is at the forefront of performance and dependability. The new EXP hub internals move the bearing stance outward, which improves axle support and stiffness. “It’s stiffer, and harder to break axles,” says Chuck, listing off the positives of this collaboration. “We’re using DT ceramic bearings in there, and they’ve been performing outstanding. They handle abuse and heavy use better than other ceramic bearings – their behavior is more like steel in terms of how robust they are. The Limited Edition wheelset gets 54-tooth hub engagement, while the rest get 36-tooth. They’re durable, dependable, very robust, very low maintenance, able to handle high torque; it’s a good, solid design. It takes a new body and cap, but the freehubs can be swapped from SRAM XD to Shimano MicroSpline pretty easily. And DT are awesome in terms of service, parts, and availability,”
When it came to developing these wheels, we took the “no stone left unturned” approach. Extensive design and prototyping. Lab testing. Revision. More lab testing. Real world testing. More revision. Individual components designed specifically to work in concert with each other. Lighter. Stronger. Faster. No half measures, built to deliver the ultimate in cross-country performance without sacrificing durability or ride quality. Wheels built the Roval way: True To YOUR Ride.