Aero / STT
The big challenge for wheel engineers is to reduce weight while maintaining aerodynamics. Typically these design elements are not available in a sub $1k wheel. Luckily, we already made the fastest wheel in the world and translated some of these into the S4.
Mercury's Seamless Transition Technology (STT), we;ve integrated the brake strip with the rest of the rim in order to eliminate any obstructions to wind flow and reduce drag-causing turbulence. The result is a wheel that shares the aerodynamics of a deep dish or solid disc, while being much lighter.
As a result, the S4 is Mercury's most popular wheel by far.
Spokes + Hub
A professional wheel builder will build your wheel by hand. The S4s come with Sapim's indefatigable Race spokes and Mercury's custom hubs. We've found this combination, particularly our low friction sealed-bearing hub, brings an engagement that's as close to immediate as anything we've seen on the market.
The front hub has an extra-wide 70 millimeter flange for reduced flex under hard efforts and confident stability at speed. Both hubs have an oversized axle that reduces to accommodate a traditional quick release and two and four oversized bearings in the front and back, respectively.
The S4's construction uses Mercury's Dual Carbon Layer Process, or DLP. DLP blends high and mid-moduli carbon fibers to tease out the best balance between the lightweight and stiffness of the former and the fatigue-resistance and durability of the latter. DLP also involves the incorporation of basalt fibers in the brake track to reduce heat build-up and increase stopping power.
This increased stopping power goes a long way toward addressing the poor braking that is one of the most common critiques of carbon wheels.