Bicycle Mechanics - Bent derailleur hanger or cage?

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View Full Version : Bent derailleur hanger or cage?


change
10-18-07, 08:18 PM
I have a Shimano Ultegra RD, number 6603 for 10sp with triple front chainring.

I know that the two cogs in the RD cage are supposed to be perfectly vertical with one another when viewed from the rear of the bike, but mine seems to not be. When viewed from above, it apears that the top cog is lined up with the left chain plate of the chain. This means that the difference between the top and bottom cog is half of a chain width. IOW, the cage seems to be bent slightly outward, AWAY from the spokes. I know the common damage to RDs comes from crashing on the drive side of the bike and bending the hanger or the cage TOWARDS the spokes, but this one is bent the other way. Not only that, but there apppears to be a slight twist to it as well, like the bottom cog is twisted a little with teeth nearest the front of the bike pointed inward. Does this make sense?

I've never disassmbled an RD before, how difficult is it? If I take the cage plates off the RD, will it be easier to see if they are twisted? They don't appear to be while the RD is on the bike. Also, the bike shifts fine and is not making any noises during operation. Could it be the RD hanger that is bent?


Deanster04
10-18-07, 08:35 PM
Take the bike to an LBS and have them check the bike alignment and the RD hanger for straightness. If you have a steel bike you can have it coldset if it is Al or Carbon you might be able to replace the hanger. Don't mess with the RD until you find out if it is an alignment issue. The Idler or pully wheels do have some play in them on Shimano RDs.

I_bRAD
10-18-07, 09:13 PM
How is your bike working? Is there a problem shifting or with noise?


change
10-18-07, 09:24 PM
How is your bike working? Is there a problem shifting or with noise?

Guess my post was a little too long because you didn't read the last sentance. :D

Yes, it shifts fine and is not making any noises.

I_bRAD
10-18-07, 09:47 PM
Well I think you'd be best to file this one under "if it ain't broke"

HillRider
10-19-07, 09:04 AM
Yes, it shifts fine and is not making any noises.

I agree that if the performance is good, don't try to fix what isn't broken.

change
10-19-07, 11:47 AM
I agree that if the performance is good, don't try to fix what isn't broken.

Ok. I guess I was getting a little paranoid after reading some accounts on BF about Ultegra RDs busting in half, getting caught up in the spokes, and causing more damage than just a broken RD. Thanks guys.

DMF
10-19-07, 11:58 AM
That's news to me. Ultegra is like rock. Pretty rock, but still rock.