Typical situation. Derailleur goes into a wheel (for whatever reason) and rear derailleur cage is bent. If you were a customer would you rather have the derailleur replaced and know it is fixed, OR have a mechanic attempt to repair it by bending it back or replacing the cage and accept the problem may not be fixed the first time?

Yes, the replacement is more expensive, but is a sure fix. Replacing parts or manual adjustment may be cheaper, but introduces doubt into the repair and in all likelihood may work in the shop only to fail in use. Then a customer would return, upset the repair failed.

My stance is replace it and remove all doubt. Been asked as a mechanic to "make do" one time too often and want some outside input.

Repair or replace?

  • I get a shop not wanting to try and fix. A shop also would never patch a tube. At home if you have the tools might be worth a try. I have bent many cheap kids bikes back. – paparazzo Mar 27 '17 at 15:11
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    Is the derailleur cage made from steel or something else ? Is it a good one or a cheap one in the first place? Is it worn as well as bent? Is the bike a finely tuned racing machine or a old clunker used for winter riding? – Criggie Mar 27 '17 at 19:10

Replacing it is the more economical option in almost all cases, especially on lower end stuff (esp. once you include labor) -- you can't source the parts for many lower end derailleurs.

On higher end parts it may be possible to send it out to a company which rebuilds derailleurs or rebuild it yourself with parts, but again, the labor and parts will likely outweigh the cost of just getting a new one (and the new one is less likely to fail; the rebuilder may make screw ups).

So, I'd almost always replace, unless I had a good reason not to (e.g. someone who insists on vintage parts and wants that vintage part repaired). Or if its a tiny deviation (which wouldn't occur if the derailleur went into the wheel; that's generally toast).


I would rather have the mechanic bend it back and offer a money back guarantee if its not perfect. Cheap and no risk to me as the customer. If you cannot (or are not prepared to) offer that guarantee, don't do it. Even if you are prepared to take the risk the customer comes back, the customer still has to come back, so won't be entirely happy with you.

If you do what the customer asks, and it does not work, it costs the customer more. Even if he understands it was his choice and won't blame you in any way, how do you know this? How do you know the customer will not 'rant off' at you, or worse, your other customers about you, for doing a 'crap' job? Whats your situation with consumer protection law - will he come back at you and say the repair was not fit for purpose and demand his money back?

If you stick to your guns, you might loose a job, but really, is it a job or customer you want to keep.

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