BB30 ZERØ Outboard Ceramic Bottom Bracket for 24mm Cranks (Shimano).-BlackTwo machined aluminum cups thread together keeping the bottom bracket stable in the frame, increasing bearing life and simplifying maintenance.This means no more squeaks, smoother operation, longer bearing life and really fast bearing replacement.Specifically designed to install cranks with a 24.00mm axle diameter (Shimano, etc.) on BB30 frames (42mm inner diameter bottom bracket shell) without the need for adapters.Bearings.Enduro ZERØ Ceramic BearingsColor.BlackBottom Bracket/Frame Interface.BB30, OSBB Specialized AlloyBottom bracket shell width.68mm.-73mmBottom Bracket Shell ID.42mmWidth over bearing.90.5 mm in 68 mm wide housing*Crankshaft shaft diameter.24.00 mmTool pattern.44mm, 16 notchesWeight.122gPackaging for retail display.Dimensions over bearing width include the supplied silicone dust protectors.Compatible with the following bottom bracket standards (42mm bottom bracket shell inner diameter):BB30Specialized alloy OSBB.Compatible with cranksets with an axle diameter of 24.00 mm.