The Ksyrium line has always offered the unbeatable combination of light weight, high stiffness, comfort and reliability. Now with added Mavic UST Road Tubeless technology to make the Ksyrium Carbon SL UST even faster. Eliminating the tube also eliminates friction, so you roll faster with greater efficiency. And now you can run lower tire pressures in the Yksion Pro UST Tubeless tires for increased comfort and a reduced risk of flats. As a bonus, the UST system including sealant weighs less than a traditional tube and tire system. Added rim width (19mm internal/25mm external) allows for increased air volume in the tires, which further improves ride quality, and the round, smooth rim profile makes it one of the most aerodynamic wheels in its category. The spokes are bladed and double butted. Using 20 in front and 24 rear creates high stiffness, low weight and long-term reliability. The Ksyrium Pro Carbon SL C also includes Instant Drive 360 freewheel system hubs for fast engagement, high axle stiffness and great durability. And if you need to service it, the tool-free design makes it simpler than ever.