High quality hybrid ceramic bearings and specially designed cups for the smoothest and longest lasting bottom brackets available BSA24: Fits all 24mm spindles on a BSA/English threaded frame and includes step-down 2-piece non-drive side reducer for use on GXP spindles. See included instructions for spacer and reducer configurations (alloy cups) Choose (Road) for low friction designed for Road use, or (Cross) for weather resistant seals designed for MTB, Cyclocross, or Commuting use 2 year warranty with annual bearing service. See KB009*