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Old 09-06-11, 04:13 PM   #1
TacomaSailor
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Derailleur Hanger moves a little - hanger bolt is tight but rotates in dropout

2008 Specialized Roubaix Elite (Triple) with about 2500 - 3000 miles on it. Never dropped or crashed. Hanger is straight and rear derailleur shifts easily and smoothly.

BUT - the hanger can move forward/backward (pivots about the hanger bolt) about 0.5mm

This problem started about 200 miles ago. The symptom was a creaking sound when I put a lot of torque into the crank. I thought it was the handlebars/headset because I had been working on those. It is not getting worse.

Today I finally isolated the noise to the rear hangar. I can make it creak by holding the front wheel against the wall and torquing on a pedal. I put my ear next to the hanger and I can hear it creak. It does take a fair amount of torque - I'm 6' & 210 pounds and have pretty strong legs. It takes about 1/2 my max effort to make it creak.

I've checked the hanger bolt and it is tight - by that I mean that I can't turn the 5mm bolt head while holding the back of the bolt (on the inside of the dropout).

BUT - the entire hangar bolt rotates easily within the dropout if I don't secure both ends of the bolt.

QUESTIONS

1) Is a little creaking and 0.5mm forward/backward movement a problem?

2) How do I break the hangar bolt loose? Using my 5mm L-shaped allen wrench - I can not turn the bolt head loose from the backing when I prevent the backing from turning. The bolt head (5mm) is clean and the slots in the backing are clean and straight. Do I just use more torque - I've read else where the bolt should be 4 - 5 Nm but this way is way tighter than that.

3) What would cause the hangar bolt to become loose in the dropout? I hope the answer is not an ovalized or enlarged hole in the dropout?

4) Can I keep riding the bike until I can fix the problem (if it is a problem)?
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Old 09-06-11, 04:53 PM   #2
reptilezs
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depending on the hanger design you may need to file it a bit because the threaded boss protrudes too far. hangers are held on with a chainring style bolt too. for the creaks. remove the hanger and grease all surfaces and reinstall. clamp wheel firmly. can also grease drop outs.
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Old 09-06-11, 05:49 PM   #3
TacomaSailor
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Using the CORRECT tool solves many of my problems!

I found and used a Park 11mm tool for chainrings/hanger bolts. With that tool I was able to get a much better grip on the slots on the backing for the bolt. Turns out the bolt was barely finger tight.

Putting in about 5Nm of torque stopped the rotation of the entire bolt assembly and stopped all the creaking.

"it is a poor workman who blames his tools" but a silly workman who is too lazy to find the correct tool.
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