Mercury Wheels M5C Carbon Road Wheelset. Blazing fast on flat terrain plus plenty light for climbing and accelerating, the Mercury Wheels M5C Carbon Road Wheelset is a super star all arounder. The rims measure 55mm, a depth that ensures superb aerodynamics and stiffness while still being plenty light for hilly terrain. The M5Cs' construction is informed by the Dual Carbon Layer Process, or DLP. Mercury blends high and mid moduli carbon fibers to straddle 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. Their increased stopping power goes a long way toward addressing the poor braking that is one of the most common critiques of carbon wheels. The M series rims are also the lightest Mercury Wheels creates thanks to a slightly different carbon layup process than their S series. The M series rims are laced with Sapim's CX Ray spokes, their most popular bladed model, which are incredibly strong as well as lightweight courtesy of their proprietary butting. The M3C wheels also utilize Mercury Pro hubs, which engage with 3 pawls for a nearly immediate responsiveness that takes advantage of the rims' low rotational inertia. The front hub has an extra wide 72 millimeter flange for reduced flex under hard efforts and confident stability at speed. Both hubs have a 15 millimeter axle that tapers to accommodate a traditional quick release and two and four over sized bearings in the front and back, respectively. Additionally, the M5C's rims are a solid 23.5mm wide, which means you can run lower PSI for a more comfortable ride that corners with unparalleled confidence. Wider rims also have some counter intuitive effects when compared to those standard 19mm rims: they actually decrease rolling resistance and increase aerodynamics.