Bent derailleur hanger

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CanucksTraveller

Macho Business Donkey Wrestler
Location
Hertfordshire
My daughter took a little spill today, she's fine but the bike hit the tarmac hard and the derailleur took a hit. The hanger has bent in a little which is forcing the chain off and into the spokes in low gear.

Is it overall cheaper / less faff to buy a new hanger or is there mileage in trying to straighten this out? The research I've done so far suggests that special tools are needed to straighten a hanger, and they look fairly easy to change. (And cheap).
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Mike_P

Guru
Location
Harrogate
£30-£40 for the proper tool to do it and that relies on the wheel being 100% true, around £10 normally for the hanger which are bike model specific.
 
OP
OP
CanucksTraveller

CanucksTraveller

Macho Business Donkey Wrestler
Location
Hertfordshire
Thanks everyone. The cage looks good, just the main body of the mech is scuffed. Thanks to all for the advice, new hanger it is.

Yellow Saddle: I did a search, it's just that it's not always that easy, results are quite mixed and often not quite what you were looking for. I'm sorry if my question put you out any.
 

screenman

Legendary Member
You can put a new hanger on it but of the frame is out. 2 minutes the right tool and the job is done.
 

wafter

I like steel bikes and I cannot lie..
Location
Oxford
FWIW I've bent them back in situ by hand before, although this was only after the bike had fallen over in isolation so less load and bending force applied, so probably a less severe bend. Worked OK but probably not very clever and couldn't get it perfectly straight (perhaps because it had work-hardened?). Didn't see the need for a tool though and was pretty straightforward to get close with a straight edge and eyeballing the alignment of the jocket wheels and sprockets. It was close enough for a little tweak on the RD adjustments to make it fine in use though.

Second time it fell over I swallowed my tightness and replaced it (although this wasn't straightforward due to part geometry differences, but I digress..).

Probably don't need to tell you this but they're usually (cast?) ally so susceptable to work hardening and fatigue; making bending it back not a great idea as it will be weaker; especially if you really apply a lot of load in an effort to get it dead straight. Obviously the greater the extent of the bend the worse this situation will be. Tbh you'll probably get away it it as I can't see one breaking in use (only if the bike falls over again) on the other, for the sake of a few quid (and especially if your work is responsible for someone else's safety riding the bike) better to err on the side of caution and replace it IMO.
 
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