Bicycle Mechanics - Rear derailleur angle troubles....

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ricohman
06-15-08, 07:47 AM
I am having some trouble with the RD on my new bike.
It seems to get out of adjustment quickly, skips gears and is noisy.
No amount of fiddling can make it as good as my older bikes.
I noticed that the angle on the RD is weird. The cage seems slanted in at the bottom.
But the cage is not bent. Both pulleys seem to be pointing outward toward the front of the bike. They cannot be aligned with the rear sprockets.
The dropout also seems tilted in at the bottom, but the bike has never even so much as fallen over. Plus the dropout is a good soild piece. I don't think it would bend this way. Welded crooked maybe?
Any ideas??
http://i23.photobucket.com/albums/b400/fj40/DSC02452.jpg


jacksbike
06-15-08, 08:08 AM
First thing-if you bought it from a bike shop, return it and ask them to throughly check it. It is possible that the rear dropouts and/or the derailleur hanger in particular could be misaligned. The SIS/index adjustment is done throught the adjustment barrel on the rear derailleur where the cable comes in. Usually the derailleur cage is perfectly parallel with the casette gear that it is under.

ricohman
06-15-08, 08:47 AM
I'm going to have to take it in tomorrow. It looks like the hanger is bent. How I do not know.
I would rather just straighten it myself but all I have is a large bolt to thread in and pull on.
The shop would have the proper tools I guess.
Can a rear hanger bend if a bike gets bumped or falls over? Maybe before I got it?
Now that I look at this pic I can see the top of the RD is slanted also.
http://i23.photobucket.com/albums/b400/fj40/DSC02453.jpg


onbike 1939
06-15-08, 01:23 PM
Better to let the shop have it. Checking the hanger to make sure it's plumb doesn't take long but is vital for good changing. I can't see from the photo if the hanger is a replaceable one or if it is part of the frame but whatever, it needs seeing to.