Mercury Wheels M3C Carbon Road Wheelset. At first blush, you might be inclined to compare the Mercury Wheels M3C Carbon Road Wheelset to other manufacturers' pure climbing wheels. And you'd be right to do so, at least when it comes to climbing. But these aren't just a one trick pony. The M3Cs' aerodynamic pedigree, low weight, and brute strength also recommend them for all the ups, downs, and flat outs of high performance cycling. They cover the demands of every terrain on every day of your cycling life. The M3Cs' 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 rims measure 30 millimeters, a depth that strikes an all purpose middle ground between straight on aerodynamics, hiding from crosswinds, and considerations of weight for climbing. 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 M3C'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.