Bottom bracket cups with 16-notch tool fittings show up across a wide range of brands and groupsets, and you need a tool that fits those notches precisely to avoid rounding them during installation or removal. Park Tool's BBT-9 is the dedicated wrench for this job. It fits 16-notch external bearing bottom bracket cups with a major diameter of 44-45mm and a minor diameter of 42.7mm, which covers Shimano Hollowtech II cups (BB80, BB5700, XT BB70, BB51, and earlier external bearing models), Campagnolo Ultra-Torque and Power Torque, SRAM/Truvativ GXP, Chris King, FSA MegaExo, Race Face X-type, Hope, Surly, Fulcrum, Phil Wood outboard bearing, and others that share the same 16-notch interface.

The tool is a double-ended design. One end engages those 16 external notches on the bottom bracket cup, and the other end fits the 8-point Shimano Hollowtech II crankarm adjusting cap — the small plastic preload cap you turn to set bearing preload before tightening the pinch bolts on the non-drive crankarm. That second end is specific to Shimano's system, so if you're running Campagnolo or SRAM cranks, you'll only use the bottom bracket cup side. The same 16-notch fitting also shows up on some Center Lock disc brake rotor lockrings, so the BBT-9 pulls double duty there if you're swapping rotors or building wheels with Center Lock hubs.

The handle is plated steel with a vinyl-dipped grip, and the length gives you enough leverage for the torque values bottom bracket cups require without needing an extension. The tool head is laser-cut for a precise fit against the notches — sloppy engagement on a bottom bracket tool means stripped cups, and stripped cups mean a trip to a shop with a vise and extraction tools. If you're doing your own bottom bracket service on any bike running a 44mm outer diameter, 16-notch external bearing bottom bracket, this is the tool that fits.... Read More