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Bending RD and RD Hanger Back Into Place?

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Bending RD and RD Hanger Back Into Place?

Old 05-03-11, 03:46 PM
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Bending RD and RD Hanger Back Into Place?

Sorry I can't get pictures that show the damage better, but here's my RD after a crash and after doing some on-the-road-bending to allow me to finish a ride:





Essentially, I think the RD hanger was bent back, plus the RD itself was bent. I'd take the bike down from the ceiling to get better photos, but my body hasn't healed enough to do that yet.

So, can I fix this myself with judicious bending, or do I need to take it in or get a replacement?

Thanks!
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Old 05-03-11, 04:42 PM
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Replace, the hangers are designed to break off, saving the frame from damage, if you bend it, it will weaken it further.
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Old 05-03-11, 04:53 PM
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no way to know if the hanger will survive the alignment process without throwing the hanger alignment tool on. if the rd is bent then toss it. new hangers will also need alignment
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Old 05-03-11, 04:57 PM
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^^^Well put. If I could get a hanger tool on it on get a feel for the amount of yield in it, then I would know. Most of the time, they can be straightened once. But if the derailleur is exactly straight it'll never shift right....
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Old 05-03-11, 05:09 PM
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What kind of bike and how many rear gears does it have?

From the picture it looks to me like a steel frame with maybe a 7-speed cassette. If that's the case, I'd just eyeball it back into line. 7-speeds aren't nearly as picky about perfect alignment as 9 and 10-speeds.

Steel frames don't generally have replaceable derailleur hangers so your only options are to leave it like it is or try to bend it straight. If you don't want to ride it like it is, you have nothing to lose by trying to bend it straight.
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Old 05-03-11, 06:31 PM
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+1. Before you buy anything bend it the best you can and see if you're satisfied. If the frame doesn't have a replaceable hanger, you can try to bend it yourself with a large adjustable wrench. Or take it to a shop, which will have a special tool that screws into the hanger and is very long. It can be rotated around the rear wheel and will get it just the way it should be.

There's not too much you can do about the derailer. Bend it if you can, replace it if you can't. Good luck, and heal fast.
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Old 05-03-11, 06:41 PM
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It looks like a steel frame to me. Most dropouts on steel frames are forged or stamped from mild steel so they can tolerate rebending from accidents like this. The traditional tool to re-align the hanger is the Campagnolo "R" tool:



It threads into the hanger and the arm is used to bend the hanger back into alignment so it lies equidistant from the rim all along the rim circumference.

If this is an indexed shifting system, these are much more fussy than friction systems and a more precise tool is often needed, but the principle is the same:

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Old 05-03-11, 07:41 PM
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A spare rear wheel will screw into the Der. hanger and can be used as a lever to align the hanger. Use the extra wheel as a guide. Both wheels will be parallel when the hanger is straight.
From the pic. the Der. itself looks OK.
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Old 05-03-11, 09:49 PM
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I use a 3" bolt in 10mm and a short pipe along with the adj wrench depending on how it needs tweaking. If It's indexed and I have problems after that I'll get the dropouts aligned too.
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Old 05-04-11, 06:09 AM
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Originally Posted by Retro Grouch
Steel frames don't generally have replaceable derailleur hangers so your only options are to leave it like it is or try to bend it straight. If you don't want to ride it like it is, you have nothing to lose by trying to bend it straight.
I agree with the frame looking like steel. But - it clearly has an aluminum replaceable hanger. In the second picture, look at the silver part the B-tension screw pushes against.
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Old 05-04-11, 09:10 AM
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It's a 1997 Specialized M2 Pro (aluminum).

Attached Images
File Type: jpg
RDSideView.jpg (68.3 KB, 21 views)
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Old 05-04-11, 09:34 AM
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Al, With a little luck only the replaceable hanger is bent. Remove it and place it on a flat surface to check.

Brad
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Old 05-04-11, 10:09 AM
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I don't see a replaceable RD, in #11 picture , unless it's painted over ,
take the RD loose send that picture, to dissuade me..

Al may just have to go shopping for another frame or bike.

Good luck

always crash on your left side, in the future..
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Old 05-04-11, 10:30 AM
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I've used a crescent wrench clamped down across the hanger to bend it back. Seemed to work well.
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