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  1. #1
    mtbr member
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    HELP! Upper Pulley Hitting Sprocket

    Topic says it. On my XTR rear derailluer, the upper pully is tight against the sprocket on the two largest sprockets. It's quite obvious sound wise, and creates a drag I can feel. I know this is not good. Somehow, it just started happening.

    I checked out the Park Tool website for some advise, they recommend tightening the 'B' screw. I tightened it all the way. No help. Didn't do anything.

    Does anybody have any other recommendations on what to try?

    I think the derailleur is pivoting too much on the mount, but it's hard to tell at what angle it should be at.

    Any ideas are appreciated. Thanks in advance.

  2. #2
    Not just famous; infamous
    Reputation: coolhandluchs's Avatar
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    Reverse the screw

    Pull off your RD, remove the B screw and screw it in from the opposite direction. The head of the screw will now rest against the hanger, and should push it further away when you reattach the RD. You may want to use a bit of loctite to keep it in place.

    This is a really common problem with XTR RDs and 11-34t cassettes. I've got the same thing going on with my setup. I'm probably going to pull the screw (after I get a new derailleur, mine's fried) and replace it with a longer one from the hardware store. Another thing to do is to keep the B screws from XT and LX RDs and use it with an XTR. For some reason, the XTR screws seem to be slightly shorter than the others

  3. #3
    Lay off the Levers
    Reputation: Bikezilla's Avatar
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    It sounds like Cool-H nailed it.

    There is also one other thing to check, if this has just recently started. Pull the der and check the b-tension return plate. I once cracked mine and the split would cause the der to ride the bigger cogs under load. Not on the workstand, only on a hard climbing effort. It may not be your problem but it's something to look for while you're down there.
    Faster is better, even when it's not.

  4. #4
    born again
    Reputation: gearz's Avatar
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    Chain too long?

    I run an XTR Rapid Rise with a Sram 9.0 11-34 and my stock B-tension screw is about 75% screwed in and I have no clearance problems whatsoever. If it just happened it could be that the tension plate broke. I run a medium (SG) cage with 2X9 (22/32) tooth rings. When I'm on my big/big combo the cage is pulled slightly foreward of being vertical up and down. This seems to pull the derailleur body foreward and provide more clearance at the guide pulley. If you're running too many links in you're chain the lower tension allows the deraileur body to pivot back which cuts down on the clearance between the guide pulley and the largest sproket.
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  5. #5
    all hail der Fuhrer Bush
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    Agree: Shorten the chain

    This seems to pull the derailleur body foreward and provide more clearance at the guide pulley. If you're running too many links in you're chain the lower tension allows the deraileur body to pivot back which cuts down on the clearance between the guide pulley and the largest sproket.

    Exactly. Take out a pair of links, and you may not even need the B tension screw cranked in.
    Reversing that screw, or replacing it with a superlong one from the hardware store, are bogus fixes.

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