The Kogel BB90 Bottom Bracket fits on Trek Carbon frames which are made with a BB90 shell. Featuring ceramic bearings, this bottom bracket is made to run like new for years on end while enhancing your power transfer. This version is designed to accommodate 24mm spindle cranksets from Shimano, Rotor, and SRAM GXP. These strong seals are designed for MTB and gravel riders to keep moisture and debris out. Kogel knows that every pedal stroke is important, and hand makes their bottom brackets to maximize your efficiency.