Compatible with 24mm/GXP spindles with included step down reducer for non-drive sideWhile 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 setupsAll Kogel Bearings T47 ceramic bottom brackets can be installed with Enduro TorqTite-compatible tool86.5mmT4724mm/GXPAlloyBlackRoad