What tools do I need to remove a square-taper bottom bracket and crankset?
By Crankworthy · Published · Updated
Three: a hex key or socket for the crank bolts (8mm on most modern square-taper cranks), a crank puller to draw each arm off the spindle, and a splined cartridge tool — turned with a large wrench — to unscrew the bottom bracket.
In order
Crank bolts: remove the bolt at the centre of each arm. Most modern square-taper cranks use an 8mm hex bolt; older ones use a 14 or 15mm socket-head bolt, sometimes under a dust cap.
Crank puller: the arms are pressed onto the tapered spindle and will not pull off by hand. The puller threads into the arm, and its centre screw pushes against the spindle to draw the arm off. Thread it in fully before pushing — a partly threaded puller strips the arm's threads.
Bottom bracket: a square-taper cartridge has a splined end that takes a matching tool, turned with a large wrench. On the usual BSA thread the drive-side cup is reverse-threaded, so it loosens clockwise.
The tools from our catalog
The CWP-7C also handles splined Octalink and ISIS arms, and the BBT-22 fits ISIS cartridges as well as square taper.
- Park Tool HXS-1.2 Pro Hex Wrench SetL-shape hex wrench set 2-10mm, workshop grade$28.95Amazon
- Park Tool CWP-7C Universal Crank PullerExtracts square taper and splined (ISIS/Octalink) crankarms via internal M22 threads$17.95Amazon
- Park Tool BBT-22 Bottom Bracket Tool20-tooth splined tool for square taper / ISIS cartridge bottom brackets
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