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How to remove your crankset

Cyclist magazine
13 Apr 2020

Need to fit new bottom bracket? Want to replace old chainrings? You'll need to get your cranks off...

Your crankset (or chainset) comprises the chainrings and cranks, as well as the spindle that connects them, which in most modern cranksets is integrated into the drive-side crank (right-hand side).

There are many reasons why you might want to remove this – perhaps to fit a new bottom bracket (the bearings that allow the cranks to turn smoothly), or to replace worn-out chainrings. The only special tool you need for this is a wrench with a suitable adapter for the adjustment cap in the left-hand crank.

Here Chuck used Park Tool’s BBT-9 Bottom Bracket Tool (£19.99, madison.co.uk), which has an adapter for Shimano crank caps built in. Our guide is based on a crankset using a Hollowtech-type external bottom bracket, but most crank systems use similar methods.

How to remove your road bike's crankset

1. Loosen the left-hand crank bolts

First, use a 4mm Allen key to loosen up the hex bolts that hold the left-hand crank arm onto the crank spindle. Make sure that you loosen them fully, but don’t remove them completely.

2. Remove the adjustment cap

Next, take the bottom bracket tool and fit the black smaller ring into the crank arm adjustment cap. If you’ve loosened the two hex bolts sufficiently, this will screw out without much effort. If it isn’t moving, go back and repeat step 1 until you can remove the adjustment cap easily.

3. Remove the crankset

The left-hand crank should now pull away from the spindle easily. Once you’ve removed it, you should then be able to pull the right-hand side crank (with the spindle attached) out of the bottom bracket.

If you find it hard to budge, you can ease it out by tapping the end of the spindle with a rubber mallet – but cover the end with a cloth and use only gentle force to avoid damaging it.

4. Clean up the bottom bracket

Use your cloth to wipe away any gunk inside the BB and inspect the shell for loose bits before checking how smoothly the bearings roll. If they feel gritty or notchy, replace the BB – if it’s an external Hollowtech type, as pictured, simply use the Bottom Bracket Tool to unscrew the old one and fit the replacement. For a Pressfit-type bottom bracket, see our guide to installation in issue 23.

5. Put it all back together

If you’re replacing the same crankset, give it a good clean. Apply a dab of fresh grease to the spindle, then push it through the bottom bracket. You may need the mallet again to ensure it goes all the way through. Grease the splines on the end of the spindle then refit the left-hand crank, ensuring it is perfectly aligned.

6. Retighten the bolts

Replace the adjustment cap, screwing it in gently using the Bottom Bracket Tool. Don’t overtighten it or you will damage the bottom bracket bearings. Use your torque Allen key to tighten the crank arm bolts; the recommend torque is usually shown on the crank arm – 15-20Nm for our Shimano crankset.