I often get bikes in that have rear gear issues without there appearing to be an obvious cause. If the cable seems ok and you’ve tried to adjust your indexing but still no joy; it could be your gear hanger, and it may be bent, cracked or loose. Hangers on pretty much all entry level bikes and above these days will have a replaceable hanger. Bend or break one of these and your gears will not function correctly whatever you do. A bent or broken hanger is a good thing though as it means you are unlikely to have damaged your frames chainstay.

A crash, your bike falling over or transit damage are the main cause of a bent hanger. They don’t always need to be out much either, just a few mm can cause havoc and this misalignment can be either a lateral twist or a bend in or out of the point your derailleur attaches. A badly bent hanger may even have sent your derailleur into your back wheel causing further damage!

A bent hanger though can be straightened with the use of a specialist tool. This comes with a couple of caveats. Once bent back the hanger will not always be 100% perfect again so even though indexing can be greatly improved, your shifting may not be spot on until you replace it with a new one. The other caveat is that there is always a risk that a straightening repair may snap the hanger; it depends on the level of damage and the quality of the hanger.

A new hanger usually costs in the region of £15-£30 and can sometimes be hard to source. I can source and fit a new hanger as part of a gear service and re-index your gearing to get you up and running again.

Follow these steps to ascertain where your gear issues may lie in your hanger:

• Looking from behind your derailleur, is your derailleur cage vertically in line with the sprockets on the cassette? If it is out of line in then its misaligned and will need straightening or replacing.
• If you feel it’s bent try to limit your gear changing to the bigger sprockets on your cassette.
• I can check the alignment of your hanger and do a check over your shifting. I won’t charge for the assessment. If work needs doing I’ll advise on parts required and give you a rough price but as mentioned above, some investigation may be required to source the hanger and get a parts price.

Bad shifting casues

I’ll be adding some similar posts to this to help you diagnose your gear issues. A lot of the time gear issues are mainly caused by sticky gear cables but worn transmission, aging gear shifters and derailleurs can also play a big role in gear shifting annoyances.