If your gears aren’t shifting properly and you can’t get them to index, a bent derailleur hanger can often be the culprit.
The derailleur hanger keeps the rear derailleur aligned perfectly with the cassette cogs and is designed to bend or break in the event of an impact. Because the hanger is typically constructed from soft aluminium, it doesn’t take a lot to knock it out of alignment.
If the hanger isn’t bent too badly, it’s often possible to straighten it, but if it’s too far gone, it’s best to replace the component.
In this guide, we’ll take you through the step-by-step process of straightening a bent derailleur hanger, as well as replacing a broken one. How to straighten a bent derailleur hanger
There isn’t a substitute for a derailleur hanger tool. Kaden Gardener / Our Media
As well as the correct-sized hex or Torx key to remove and reinstall the rear derailleur, you will need a derailleur hanger alignment tool for the job.
These can be expensive, but there isn’t a substitute. If you own multiple bikes, it’s worth investing in, or perhaps sharing, a tool among your riding friends.Bear in mind you run the risk of the derailleur hanger snapping, because you’ll weaken the material by bending it back.Some suggest using the jaws of an adjustable spanner to bend it back in place by eye, but we wouldn’t recommend this – it’s more likely to break given the increase in force and it won’t provide an accurate gauge of where it […]