R45D hubs combine low-drag 45-tooth RingDrive(TM) 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 and completely re-buildable with our R45 Hub Service Tool Specifications Rear Axle12mm Thru x 142mmCassette Body TypeShimano HG 11/12-Speed RoadCassette Body TypeShimano HGColorBlackSkewer IncludedNoBearing TypeSealed CartridgeDefined ColorBlackSpoke InterfaceJ-BendHub Drilling24Hub/Brake CompatibilityCenter-Lock Disc