If you have bent a crank or just want to upgrade your crankset, knowing how to replace it yourself can be pretty useful.
In the video below we demonstrate the procedure using a Shimano Hollowtech crankset – but the procedure is the same for FSA MegaExo and other similar systems. Similarly, a Hollowtech-type crankset on a mountain bike will be the same as a Hollowtech-type crankset on a road bike.
Video: How to replace a crankset
This video is part of the Park Tool Maintenance Monday series. You can purchase the Park Tools used in the video at a number of dealers across the UK and internationally. For more maintenance videos, subscribe to the BikeRadar YouTube channel.
Tools for the job
- Torque wrench
- Hex keys
- Bottom bracket removal tool
- Rubber mallet
How to replace a crankset
Before you start, make sure the crankset you want to fit is compatible with the bottom bracket you have. It’s advisable to do this at the point of purchase, because different bottom brackets and cranksets aren’t compatible.
Check what type of bottom bracket system you have and make sure the crankset is compatible
1. Remove the cranks
Undo the pinch bolts from the left crank using a hex key. Remove the plastic preload cap from the left-hand crank with the plastic part of the bottom bracket removal tool.
Remove the plastic preload cap
You should now be able to remove the crank from the axle.
Partially tap out the axle and right-hand crank from the bottom bracket with the palm of your hand – you can use a rubber mallet if it’s seized.
Remove the chain from the chainring, and carefully rest it on the bearing cup. Fully remove the driveside crank and chainrings.
2. Fit the new crank
Insert the driveside crank through the bottom bracket, passing it through the chain first.
Hold the frame and give the crank a tap with your palm – don’t use a hammer, it’s not needed and will stress the bearings. Return the non-driveside crank to the axle.
Return the plastic preload cap to the thread and wind in by hand, finishing off with the bottom bracket tool. This should now have taken out the slack between the cranks and they should be firmly in place.
Finally, tighten and torque bolts on the crank. These need to be tightened as a pair, so wind one until it becomes tight, then repeat with the other. If you have a torque tool, tighten to 10Nm both sides, then 12, 14, and so on, until you reach the stated torque.
Your bike should now be ready to test ride in a safe car-free area.