Removal & Disassembly of Bicycle Cranks

Traditional square-taper mech

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Occasionally, you’ll want to remove your cranks for cleaning or replacement of worn chainrings. Don’t be intimidated; it’s not a difficult job, as long as you follow a few basic rules.

Removal

Crankset tools

A couple of tools are required: A bolt removal tool—either an Allen wrench or spanner—and a crank puller.

First, extract crank bolts with the appropriate wrench (turning bolts counter-clockwise).

Turn the head of the puller (clockwise) into the threads in the centre of the crank arm and snug tight.

Depending on the tool, turn the handle of the puller (clockwise) or tighten inner bolt with wrench. This will extrude the push pin against the bottom bracket spindle and push the crank off (toward you).

Some cranks feature “self-extracting” crank bolts. These may be stock or aftermarket, like the (discontinued) Sugino Autex units. A single Allen wrench removes the crank.

Dismantling drive-side crank

All mid-level to high-end cranks have removable chainrings, secured with chainring bolts (usually 5mm Allen).

The middle ring is most often the first to need replacement on a triple crank. Whichever you replace, make sure you buy the correct ring for the job. Ramped chainrings are manufactured to optimize timing and combinations are specific. If you’re unsure, consult your friendly local bike shop.

Remove chainring bolts

Chainring bolts

Begin by removing the inner ring on a triple crankset. It is usually bolted directly into the crank spider. Remove the chainring bolts holding large and inner (or middle) chainrings together, either side of the spider.

This is a good time to clean all components thoroughly.

When reassembling, verify that the pin on the outer ring, that keeps the chain from jamming behind the crank arm, is aligned with the crank and that any “timing” markers (diamonds on Campagnolo) are are also lined up correctly.

Make sure all bolts are snug (Campag recommends 8 N.m (5.9 lb.ft) for chainring bolts.

Line up timing markers

Replace the cranks. Again, Campag’s torque recommendation for crank bolts is 32÷38 N.m (23.6÷28 lb.ft) Check all bolts regularly.

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