The Mavic Cosmic SL 45 Disc sits at a rim depth that pulls double duty: shallow enough to hold a line in a crosswind, deep enough to carry speed on flat and rolling terrain without fighting the bike. The 23mm internal width opens the tire to a rounder profile on 28mm and wider rubber, which adds road feel and compliance on surfaces that would otherwise vibrate a narrower rim apart. What Our Gearhead(R) Experts Are Saying:"The engagement snaps in fast enough that the power gets to the road before I've finished thinking about the pedal stroke. These have stayed smooth through a full season of wet training rides without touching the bearings, which is what keeps them on the bike instead of on the bench."