The Shimano XT BB-MT800-PA Bottom Bracket steps up the game with durable bearing seals and smaller bearings than previous models to reduce friction and provide a smooth pedal turn every time you clip in. It's compatible with 89. 5 to 92mm-wide shells with a 41mm internal diameter. This bottom bracket pairs with MTB 24mm Hollowtech cranksets and will fit frames with the BB89 and BB92 bottom bracket standards.