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Old 09-03-08, 09:40 PM   #1
shams42
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rear derailleur question

I've been having some shifting problems on my bike. My mechanic thinks its a bent RD hanger. It's been bent several times before and he's bent it back for me but I think metal fatigue has set in. I got a new hanger today and removed the derailleur to install it. (The new hanger ended up not the being the right part, so I had to place another order ).

I noticed that while the tension pulley spins without much resistance, the guide pulley has a lot of resistance. Is that normal? Is there something wrong with my derailleur? At the very least, it can't be very efficient.

The bike is a 2007 Scattante Comp CFR with only about 1,600 miles on it. The drivetrain consists of 105 shifters, a (recently upgraded) R700 compact crankset, and an Ultegra rear derailleur.
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Old 09-04-08, 09:28 PM   #2
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2 used Shimano RD's I have, both have free spinning guide pulleys.
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Old 09-05-08, 03:13 AM   #3
Torchy McFlux
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Don't know what you mean by "a lot of resistance". They won't spin completely freely, but if it's more than a little drag from a rubber lip-seal, then something's wrong.
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Old 09-05-08, 07:19 AM   #4
mcoomer
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Just pick up some new pulleys if you feel like they're not spinning freely.
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Old 09-05-08, 08:07 AM   #5
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If you've bent the derailleur hanger "several times before" it is likely you've also damaged the derailleur itself. You may have bent the pulley cage and that's causing the binding in the guide pulley.

As others have mentioned, the guide pulley should turn quite freely with only a very slight drag due to it's seals. It should certainly turn as freely as the tension pulley. A new guide pulley won't fix the problem if the cage itself has been deformed.
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