High quality hybrid ceramic bearings for the smoothest and longest lasting bottom brackets available. While Trek T47 bottom brackets are 1mm narrower than standard 86.5mm wide T47 shells, this falls well within the adjustment range of any crank set. The same bottom bracket can be used for both setups. All Kogel Bearings T47 ceramic bottom brackets can be installed with Enduro TorqTite-compatible tool. 24/GXP version 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*