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derailleur pulley rubbing large cog(10 posts)

derailleur pulley rubbing large cogDougSloan
Jul 20, 2003 5:01 PM
This is a mtb question, but I can hardly ever get answers over at mtbreview, and I'd imagine this should be the same for road bikes, anyway.

My XTR long cage rear derailleur upper pulley rubs up against the 34 cog (XT cassette), even with the B adjustment screw all the way in. I can't think of anything else to do to get more clearance. It shifts normally, but it's just irritating to hear, and I wonder if it's not good for the drivetrain. Any ideas? Thanks.

Doug
re: derailleur pulley rubbing large cogjohnrg
Jul 20, 2003 5:34 PM
My old XTR did the same even with the screw all the way in. I had that bike for 4 seasons and never had a shifting issue. I think it was common but it did bug the hell out of me. Anyway...2003 XTR doesn't have the same problem as far as I can tell.
What about using an 11-32 cassette? NMTarheel71
Jul 20, 2003 6:17 PM
Shorter chain, that's about your only option (nm)Kerry Irons
Jul 20, 2003 5:47 PM
will that pull the pulleys away from the cogs? nmDougSloan
Jul 20, 2003 7:32 PM
Easy to test in your setup. (nm)Kerry Irons
Jul 21, 2003 4:42 PM
makes sense; just throw it in the big ring... nmDougSloan
Jul 22, 2003 7:16 AM
re: derailleur pulley rubbing large cogdivve
Jul 21, 2003 12:37 AM
Two cheap solutions:

1 use a longer screw for the B-tension
2 thread in the existing screw from the other side

The latter might work better, as the longer screw risks threading past the stop on the frame or hanger. You could also use a combination of longer screw and reverse inserting it.
Longer B screwSteve Young
Jul 21, 2003 6:57 AM
I think replacing the B screw with a slightly longer one has been found to solve the problem for some people on MTBR. I haven't tried this myself but IIRC it was discussed on MTBR in the general forum a few months back. It's a problem that a number of people have experienced but I can't remember the exact cog they were using (34 sounds familiar though).

Steve
re: derailleur pulley rubbing large coglitesp
Jul 22, 2003 8:37 AM
Doug,

I had the exact same problem with a DA setup using a 12-27. Someone suggested shortening the chain by a few links. That actually worked, except I couldn't get into big and big anymore. Shimano tech support said that my problem is normal at the derailleur capacity limit. I've even replaced it with a new derailleur only to see a slight but temporary improvement. I'm guessing the Shimano pivot springs aren't always consistent and cold set after a short time.

Try checking you chain length first to see if it isn't already a link longer than it needs to be.