The Mavic Cosmic SL 65 Disc runs deeper than most riders expect to take into a training block, but Adaptive Layup construction places carbon fiber only where the rim needs it, pulling weight back out of a 65mm profile without stepping away from the depth that drives speed on flat and rolling terrain. The 23mm internal width seats 28mm and wider tires for a contact patch that holds its composure on surfaces that would punish a narrower rim. What Our Gearhead(R) Experts Are Saying:"At 65mm I expected to be managing the wheel in crosswinds, but the rim profile stays composed enough that I stopped checking the forecast before rides. The power delivery is immediate and the wheel holds speed between efforts in a way that a shallower rim doesn't."