Ask Jaroslav Kulhavý, and he'll tell you—every gram counts in cross country racing. But with XC tracks becoming more aggressive than ever, just being a flyweight wheel is no longer sufficient. Now, wheels need to be as tough and stiff as they are light, with all of the handling characteristics that seasoned XC riders have come to expect. These days, wheels need to be more like the new Control SL 29 with Torque Tube.
When our riders asked us for the ultimate cross country wheels to pair with their RockShox RS-1, we knew that they were really asking for some pretty specific features. They had to be light in order to be low in the inertia and weight departments, strong enough to take on rocks and roots on a short-travel race bike, and wide enough so that the tire profile was optimized for both traction and rolling resistance—not an easy feat.
To check all of these design boxes, we started by looking at our Traverse SL rim to see if we could extract the wide-rim benefits while keeping the weight at, or below, the previous Control SL—the existing benchmark. Based on the width we knew was ideal for the desired ride characteristics, we tuned the rim shape to optimize the stiffness, weight, and ride quality of the system as a whole—too tall and the wheel rides too stiff, too shallow and the wheel is too flexy. Our engineers meticulously went through rim shape developments to find the perfect balance and optimal geometry, and after fine-tuning multiple layup iterations and schedules, we ended with a 25-millimeter internal width rim that's approximately the same weight as the previous Control SL.
Being able to add material and width (3mm to be exact), without a weight penalty makes for a stronger XC wheel, but we weren't content settling with just an increase in strength. With our goal being the fastest race wheelset available, we took the new and old rims, paired them with a set of size 2.0 Fast Trak tires, and performed rolling resistance tests at both 20 and 30 PSI. The result? The new, wider rim tested faster at both pressures, confirming our line-wide hypothesis that wider is not only stronger, but also faster.