The Mavic Crossmax SL Ultimate 25 29in Boost Wheelset is a lightning-fast cross-country wheelset made of carbon fiber and featuring Mavic's Infinity hub technology. The strategic adaptive carbon layering process makes for a lighter rim that maintains the same ideal durability. The Instant Drive 360 freewheel gives us a double ratchet system for reliability and fast engagement on the trails. The 25mm inner diameter offers the best balance of efficiency and traction, while the tubeless-ready setup and the ability to run up to 2. 4-inch-wide tires give us the grip and traction we need for aggressive cross-country riding and racing.