As this is not a brand new wheel, it may not feature the full original technical specification and is subject to change.
Specialized set out to create a wheelset that was built purely for speed but one that didn't just perform well in a straight line. That is why they developed the CLX 64 as the fastest wheel they have ever tested. Not only is it the fastest in the tunnel, but its prestige has been verified with Gold Medals in the men’s road race, time trial, and team time trial at the 2016 UCI World Championships.
64mm was chosen instead of 65mm as it's simply tested faster. Down to the millimetre is how deep testing goes. Having an in-house wind tunnel allows Specialized 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, 64mm was found 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. 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, Specialized focused on the wheels as a system, not just a rim with “other parts,” and Aero Flange (AF) hubs play a significant role. Designed completely in the Win Tunnel, 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. To make sure they checked all of the feature boxes, they also made the rim tubeless-ready.
To top off the multitude of performance features of the rim, the highest quality build components were chosen to pair the CLX 64 rear with. Starting with 21 DT Swiss Aerolite bladed spokes, which test faster than their round counterparts in the Win Tunnel, Roval hand-laced the 64 rim to their AF hubs that house CeramicSpeed’s legendary bearings and DT 240 hub internals. Machines make mistakes and mistakes aren't something they're ok with, so Roval have real people lace each wheel by hand.