Chris King R45D Rear Hub - 12 x 142mm, Center-Lock, XDR, Matte Jade, 24HR45D hubs combine low drag 45 tooth RingDrive system, a lightweight hub body, and legendary made in house bearings. The result is the increased power and modulation of disc brakes, the fast, smooth rolling speed of our bearings, and the superior responsiveness of our RingDrive engagement system when you put the power down. Patented RingDrive system with 45 simultaneously engaged points of contact for virtually drag free engagement Easily serviceable