Specialized Roval CLX 64 Disc – Rear

When we set out to create a wheelset built purely for speed, we wanted to make it more than just fast. Not that being fast wasn't a priority, but we were tired of wheels that only performed well in a straight line. In the end, we developed the CLX 64 Disc, the fastest wheel that we've ever tested with all of the performance benefits of disc brakes we have come to love. This iteration has a more impact-resistant rim, a disc-specific carbon layup that optimises stiffness and weight, and incredible brake modulation and power in all conditions.One of the first questions we get about the CLX 64 is, "Why 64mm instead of 65mm?" To put it simply, it's because 64mm simply tested faster than 65mm. One millimetre - that's how deep our testing goes. Having an in-house wind tunnel allows us to run every possible variation, and after two years of development, 80 variations in rim design, and nearly 300 hours studying tyre and frame interactions in the Win Tunnel, we found 64mm to be the fastest iteration for normal riding conditions. In fact, it's even faster than the 80-plus-millimetre-deep wheels they were tested against. Being able to use a shape that's nearly 20mm shallower than the competition, yet just as low in drag, makes for a wheel that has drastically less side force and steering torque. This translates to less buffeting and more confidence in even the gustiest winds.Another positive of a shallower rim depth is the reduction in weight that follows using less material. Many deep carbon wheels feel "slow" due to their high inertia value. What's that? Inertia is the amount of force it takes to accelerate or decelerate, and wheels that are built around heavier rims lack the liveliness that many riders crave. Being over a half-a-pound lighter than the other wheels in its aero category, the CLX 64 accelerates, decelerates, and changes direction with less effort.The rim is not the only component of the CLX 64 that contributes to its aero prowess, though - in order to create the fastest wheels, we focused on the wheels as a system, not just a rim with "other parts," and our Aero Flange (AF) hubs play a significant role. Designed completely in the Win Tunnel, our AF hubs feature an incredibly small frontal aero, without sacrificing stiffness, making them aerodynamically efficient.Taking the advantage a step further, these wheels were developed to work in harmony with modern-width 24C tyres. The 21mm internal rim width spreads the tyre out, in this case to 26C, making it seamlessly meet the rim. Not only does this create a system with low aerodynamic drag, but one that has exceptionally low rolling resistance and inspiring grip in the corners. And to make sure we checked all of the feature boxes, we also made the rim tubeless-ready.To top off the multitude of performance features of the rim, we chose the highest quality build components to pair the CLX 64 with. Starting with DT Swiss Aerolite bladed spokes, which test faster than their round counterparts in the Win Tunnel, we hand-lace the 64 rim to our AFD hubs that house CeramicSpeed's legendary bearings and DT 240 hub internals. Why hand-built? Machines make mistakes and mistakes aren't something we're ok with, so we have real people lace each wheel by hand.