The Mavic Cosmic S 42 Wheelset is a lightweight carbon fiber wheelset built for our fastest training rides and race-day efforts. The wind-tunnel-tested construction keeps us flying through the wind with optimized aerodynamics, using a 42mm rim height and flat spokes to maximize speed and stability at top speed. The lightweight carbon fiber helps us easily climb to the canyon's top, and the 21mm internal width maximizes tire volume for increased efficiency and cornering performance.