I bent the (steel) derailleur hanger on my 9spd cassetted (steel) Bianchi Volpe about 1.5 yrs ago, and I just did it again, but worse. This time the derailleur got sucked into the wheel and really did a doozy with the actual hole stretched and deformed.

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Is this a lost hope or is it fine to ride, so long as I can straighten it / re-tap the whole and get it shifting?

I suppose my only options are to add a new hanger if that is even possible or make it a single-speed.

Update To those who may experience the same thing, I was able to successfully bend this back into place and get everything shifting well, despite the hole now being deformed (the derailleur still threaded properly after bending without re-tapping the hole).

  • If the frame is reasonably valuable, a good frame guy could fix it. On that bike the dropouts are probably bronze castings, and they can be brazed by an experienced welder. (There is a reason for those plastic spoke shields, as much as they're sneered at by hoity--toity cyclists.) Sep 18, 2013 at 20:17
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    Daniel, I've never seen a bronze dropout. They might exist, but it seems unlikely as bronze is not strong enough. Aside from that, yes, any framebuilder who works with steel will be able to replace the dropout. It will be expensive - you'll need to repaint the frame at the end. If it's an older Volpe it's quite a nice bike - sheldonbrown.com/volpe.html
    – Móż
    Sep 18, 2013 at 22:47
  • Thanks! I'm not sure there is a frame builder around my town, and I am living in Norway which is notoriously expensive. I am pretty certain my whole frame, including dropouts, is steel. Sep 19, 2013 at 11:00
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    How you bend it back is a factor. You want to spread the force. Start with pressing it flat with a vice.
    – paparazzo
    Jun 3, 2014 at 13:51
  • So how did You fix it? Because I have same issue and don't know what to do.
    – curious
    Oct 1, 2018 at 22:55

3 Answers 3


There are several suppliers of universal derailleur hangers. The intended use is to mount a modern derailleur to vintage bikes. At one time the derailleur hanger was part of the derailleur and mounted under the axle nut. Cambria Bike.com Harris Cyclery both have several models that start at $1.00. You could also try to find one of the older derailleurs like a Shimano Tourney mega range that have the hanger built onto the derailleur they can be had for under $25.

  • I've had things running fairly well after the rebend, but I'd like to go with an add-on hanger, BUT there are so many. Do you have any suggestions on how to find a hanger suited for my 2006 Bianchi Volpe? Thanks again!!! Jul 30, 2015 at 11:43
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    You need a universal one as mentioned. Your frame has an integrated hanger so a modern model/brand specific replacable type will not fit. You need a universal type.
    – mikes
    Jul 31, 2015 at 16:02

the actual hole stretched and deformed.

This is bad, if you can't thread the derailleur back in, it's done. You could try bending it back and possible re-tapping it and see if the derailleur will thread back in. After all, if that doesn't work you haven't lost anything.

I suppose my only options are to add a new hanger if that is even possible or make it a single-speed

There are options. Some bike shops will still do frame repairs like this, but it will cost you. Replacing a rear dropout/hanger isn't too tough but requires a set of skills that is starting to become less and less common. The single speed option is, of course, still a viable option though.

EDIT: Incorporating another answer: if it's a replaceable hanger, this is a really easy, minor fix. Just replace the hanger and you're good to go.

  • So if I can re-tap it, etc. would you say it still safe to ride and stuff? :) Sep 18, 2013 at 15:28
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    If the derailleur doesn't move around or is loose, then I'd say so. It doesn't look like metal has been stressed too much where it would break, but it may be easier to bend again.
    – Aaron
    Sep 18, 2013 at 16:18
  • It's very unlikely that anyone would paint a removable derailleur hanger that colour, so I'd bet it's part of the frame based on that alone.
    – Móż
    Sep 18, 2013 at 22:45
  • Yes, it is part of the frame. I went with mikes answer, as that was what I was hoping was out there, but your is helpful. Thanks. Sep 20, 2013 at 9:03
  • If the hole has been enlarged such that the derailleur cant thread back on, you could tap out to a slightly larger thread and add a heli-coil (to restore the original thread) - any competent machinist (or even a confident home mechanic) could do a job like that
    – Penguino
    Oct 1, 2018 at 23:59

Derailleur hangers are usually made from soft aluminum that will not withstand bending/straightening without cracking. That is so to protect the dropout during this type of mishaps. In my experience, a hanger can be straightened a second time and it will look safe, but once riding, vibration will make any existing crack expand inadvertedly, until the derailleur just falls off along with a chunk of hanger. If it happens while pedalling softly you will feel it and hopefully stop the bike before any further damage occurs, in other situations the derailleur can get caught in the spokes an anything can happen from there.

In my opinion the best option is to get a replacement hanger for your frame, or to get one fabricated.

You may be able to get the replacement from the original frame manufacturer, or from derailleurhanger.com, or from http://wheelsmfg.com/products/derailleur-hangers/all-derailleur-hangers.html. There may be some other options to buy hangers, maybe secondhand...

Derailleur hangers are not too hard to elaborate, most of them are rather flat with perpendicular bolt holes, so they can be made with hacksaw, and a press drill, then a tap and some sandpaper. However, if you are not confident that you can cut the piece, or don't have a source for the aluminum, maybe a local industrial shop may be able to reproduce it. They have all kinds of precision machinery and measurement tools, just bring them the bad hanger, straightened if possible and explain what is it and what you need. In case my English is not good enough and I got the terminology wrong, I'm referring to the kind of shop where they rectify car engine blocks an other engine parts. If they won't accept the job, maybe they can at least provide you a piece of aluminum from an engine block that is damaged beyond repair. I've got replacement parts made like this a couple of times, including bike suspension linkages.


I rushed my answer and did not notice the OP's bike is a CrMo frame with a fixed hanger, so I answered based on a replaceable hanger frame. This first part of the answer is valid for an aluminum replaceable hanger.

As far as I understand, CrMo can be bent a few more times than aluminium, so it should be safe for a second straightening. I've seen the process of "unbending" aluminium hangers, and it is done by fixing the (removable) hangers to a vise and then gently hammering it with a small mallet, attempting to move the bent part only a little at a time. It was explained to me that is is done this way to avoid creating bigger stress in the piece. I guess this is valid for your case too, except maybe that it is more difficult to fix the whole frame to a vise.

It is very important that the bolt hole gets properly aligned, that is, a bolt screwed in the hanger should be perfectly parallel to the wheel/cassette axle, so the derailleur can be properly adjusted. When there is misalignment, some shifts never get to happen smoothly or to stay in mesh.

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    Of course, this is assuming the OP has a replaceable hanger.
    – Aaron
    Sep 18, 2013 at 19:15
  • @Aaron, you are right, my bad not taking a good look at the picture.
    – Jahaziel
    Sep 18, 2013 at 20:08
  • The best evidence I have is that that's a steel frame, and the dropouts would be bronze, not aluminum. Sep 18, 2013 at 20:18

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