If we haven't already, investing in a set of carbon clincher hoops for training and racing is something we all plan on doing at some point. It's something of a no brainer. The speed and aerodynamic benefits of carbon rims are well proven and worthwhile, but the one area in which carbon clinchers not only fall short of receiving glowing reviews, but outright fail at times, is braking. Mavic's Cosmic Carbone 40 Wheelset loves to go fast, but not at the expense of being able to stop. To achieve this, Mavic engineered an entirely new rim construction for the Cosmic Carbone rather than just a new braking surface or brake pads, and the French firm's quest to get it right shows in the wheelset's bombproof durability and incredibly responsive braking. The key to a carbon rim that won't fail under braking is in its efficiency at dissipating heat. Rather than trying to mitigate the issue of heat dissipation only at the surface of the rim, Mavic chose to make an entire rim that would respond better to heat, starting with a Maxtal aluminum bed. Aluminum has long been known for its ability to dissipate heat and resist high temperatures better than carbon, enhancing the durability and braking capability of the entire structure. The lightweight aluminum 'rim bed insert' that Mavic uses also holds air pressure better than full carbon, making it an early adapter of the aerodynamic clincher trend. The Maxtal aluminum is a higher grade than what's commonly used in aluminum bike components, offering an improved strength to weight ratio over its more common 6061 alloy counterpart. Atop the aluminum, Mavic then uses its proprietary TgMAX heat treatment process to carefully hand layer 3k carbon layers from the bead to the tip of the fairing. The rim is next placed in a mold to permanently bond the layers together, with spoke holes drilled only through the inner rim wall, which is itself reinforced with an aluminum insert to increase structural integrity. The result is a lightweight, ...