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Bent derailleur (hanger is straight)

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Bent derailleur (hanger is straight)

Old 12-01-14, 01:13 PM
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Bent derailleur (hanger is straight)

I crashed over the weekend and had the derailleur hanger realigned at a shop today. With the hanger straight, the cage now sits at a disturbing angle: the lower pulley is quite a bit further outboard than the upper pulley, when viewed from behind the bike.

A. Any idea how this could have happened? The impact was inward. The part is a Shimano XT Shadow, if that matters.
B. The bike shifts fine but the look disturbs me. Any suggestions for leaving it alone or taking it apart and bending the cage in a vice?
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Old 12-01-14, 01:54 PM
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A : No.. B: whats the real problem? .
The bike shifts fine but...


.. If you dont want to leave it alone, then, Buy a brand new one.
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Old 12-01-14, 03:11 PM
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You already know how it happened. There's no rule that says only a hanger will be bent in a collision. In my experience straightening a bent/twisted rear derailleur is very difficult and frustrating, even with a friction system. With a narrow spaced indexed system it's usually not worth the effort. But if the derailleur works in all gear combos then either try not to be disturbed by the appearance or purchase a new derailleur.

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Old 12-01-14, 03:38 PM
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Your shop straightened the hanger but not the derailleur? Why didn't the straighten the derailleur? Maybe they didn't feel it could be done right. If you trust them, have them put a new derailleur on.
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Old 12-01-14, 03:45 PM
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It is really hard to straighten a derailleur, especially when they are alloy and the system is indexed... it might be a temporary fix but over the long term swapping the dertailleur is the best plan. Once can also salvage the old derailleur for jockey wheels and fittings to service the replacement down the road.

Aluminium develops stress fractures and a failure of the derailleur can have some pretty serious consequences... a new Shadow derailleur will run $50.00 on sale (Universal Cycles).

Old derailleurs with steel cages and friction systems tend to be more forgiving.
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Old 12-01-14, 09:14 PM
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There a number of possibilities, but before you even consider them you have to answer this question.

Is there a problem to fix? The RD is shifting OK, and you don't report a functional problem, so what are you going to fix, and how will that make things better?

Now, if you decide that things aren't WORKING OK, then you have some options. First of all, it's very rare for RD's to get bent between the upper and lower bodies, so either the hanger alignment is off, the cage is bent, or the upper pivot bolt is partly torn out of the hanger (or cross threaded) so the RD is mounted crooked on a straight hanger. These can be diagnosed by the naked eye, and the RD cage can be further checked with a straight edge, or by removing the chain and eyeballing to see if the pulleys are in line, and in the same plane.

So feel free to do some diagnostics, but don't start "fixing" anything until you know it's broken.
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Old 12-02-14, 08:28 AM
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For peace of mind and proper future operation, it would be better just to get a new RD.
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