Results 1 to 10 of 10
  1. #1
    mtbr member
    Reputation:
    Join Date
    Aug 2004
    Posts
    3

    Rear derailleur hits cassette

    The upper pulley gear on my XTR derailleur is way too close to my cassette. It runs right against the cassette gears on the biggest gears. I've tried adjusting the "B-Screw?" (the screw that pushes against the tab on the derailleur hanger) in and out all the way with no success what-so-ever. Adjusting the cable does not seem to do it. Nothing is bent or broken anywhere. The bike is about 3 years old but really has not been used too much, it's mostly been sitting. Do I have a weak spring or something? I've tried just about everything, so any help is appreciated.

  2. #2
    Complete Bastard
    Reputation: mward's Avatar
    Join Date
    Apr 2004
    Posts
    2,282
    Stop adjusting it with the bike upside down.

  3. #3
    mtbr member
    Reputation:
    Join Date
    Aug 2004
    Posts
    3
    Well, I guess I did say any help... Anybody else have an idea?

  4. #4
    Complete Bastard
    Reputation: mward's Avatar
    Join Date
    Apr 2004
    Posts
    2,282
    Most derailleurs will drag on the top cog of a 34 t cassette when the bike is upside down, but not when it's right-side up. If it does it when it's right side up, shorten the loop of cable on the derailleur.

  5. #5
    Do It Yourself
    Reputation: Homebrew's Avatar
    Join Date
    Jan 2004
    Posts
    5,722
    Quote Originally Posted by mward
    Most derailleurs will drag on the top cog of a 34 t cassette when the bike is upside down, but not when it's right-side up. If it does it when it's right side up, shorten the loop of cable on the derailleur.
    Shortening the housing loop is not the best idea. You should adjust the b-tension screw. If it's maxed out, you can either screw it in backwards or you can try a longer screw.
    Long Live Long Rides

  6. #6
    Complete Bastard
    Reputation: mward's Avatar
    Join Date
    Apr 2004
    Posts
    2,282
    Quote Originally Posted by Homebrew
    Shortening the housing loop is not the best idea. You should adjust the b-tension screw. If it's maxed out, you can either screw it in backwards or you can try a longer screw.
    If he's got a giant loop of cable on there it can put tension on the derailleur in the wrong direction. Obviously if it's at the proper length, shortening it is not a good idea. He indicated he already adjusted the b tension screw thus I was looking for other answers.

  7. #7
    mtbr member
    Reputation:
    Join Date
    Aug 2004
    Posts
    3
    Sounds like good info guys. I assume the housing loop is inside the body somewhere that I cannot see. I can see how getting a longer tension screw would solve it though, the one I have is maxed out. Sounds like maybe this housing loop may be out of adjustment? Can it be adjusted without getting in deeper trouble?

  8. #8
    all hail der Fuhrer Bush
    Reputation:
    Join Date
    Mar 2004
    Posts
    1,635

    Here's the scoop

    It's not your cable housing being too short or too long or too anything else. You've already cranked the B tension screw all the way in and the issue persists. Reversing the screw is bogus, you can do it, but it's still bogus.
    Why you have the problem: Derailleur hanger dimensions vary widely. Some are long, others are short. Yours is probably on the short side.
    HOW TO FIX IT: Shorten your chain. Yes indeed, sounds nuts. Check it out: Put your bike in the stand, shift into the granny ring and the large cog, that's the combo that causes the upper pulley to get closest to the large cog, where it presses the chain up against the cog, making grindy noises. I bet it doesn' do it in the middle ring/large cog, right? So, you're in your lowest gear. Now grab the lower chain run and pinch a pair of links together to simulate shortening the chain by a pair of links. Watch as the derailleur cage is pulled farther forward, and how that causes the upper pulley to be rotated down and away from the large cog. There ya go. Shorten your chain by a pair of links. Or more if it's way too long, but probably one pair of links will do the trick.
    You may or may not then be able to shift into the big/big gear combo, so be aware of that and don't force it if you can't. Shouldn't be a problem,never has been for me.
    Note: The above tip about running a shorter chain will allow you to vastly exceed shitmano's recommended largest cog rating on its derailleurs. You should be able to run a short cage road derailleur -- 105, Ultegra, DuraAce, etc. on a gear cluster with a 34t large cog with no rubbing, assuming you don't use the big ring with the largest rear cog. I got bikes here with 105 and Ultegra short cage derailleurs rated as 28t max, shifting fine with 34t cogs. You're welcome.

  9. #9
    mtbr member
    Reputation:
    Join Date
    May 2004
    Posts
    73

    I have....

    Quote Originally Posted by J-Kid
    The upper pulley gear on my XTR derailleur is way too close to my cassette. It runs right against the cassette gears on the biggest gears. I've tried adjusting the "B-Screw?" (the screw that pushes against the tab on the derailleur hanger) in and out all the way with no success what-so-ever. Adjusting the cable does not seem to do it. Nothing is bent or broken anywhere. The bike is about 3 years old but really has not been used too much, it's mostly been sitting. Do I have a weak spring or something? I've tried just about everything, so any help is appreciated.
    a 32T rear cassette and my r der rubbed on it. I tried longer screw, helped marginally, as screw slips off restraint before you can go far enough. Shortening cable housing into rear of der is what worked for me.

  10. #10
    Don't touch me!
    Reputation: beeristasty's Avatar
    Join Date
    Jan 2004
    Posts
    775

    Give this man a cookie!

    This worked for me a couple years back when I built up my bike. It sounds freaky, but it works.

Similar Threads

  1. If you need to know this.
    By KevinVokeyJ24 in forum General Discussion
    Replies: 14
    Last Post: 12-24-2004, 08:40 AM
  2. Replies: 22
    Last Post: 10-29-2004, 04:32 AM
  3. Rapid rise rear derailleur with Rapid Fire shifters
    By speedyMTB in forum Drivetrain - shifters, derailleurs, cranks
    Replies: 1
    Last Post: 07-21-2004, 02:35 PM
  4. Shifter compatibility of Shimano XT rear derailleur
    By bobalouie76 in forum Drivetrain - shifters, derailleurs, cranks
    Replies: 2
    Last Post: 04-12-2004, 10:59 AM
  5. Shimano LX rear derailleur adjustments
    By joejm14 in forum Beginner's Corner
    Replies: 2
    Last Post: 03-08-2004, 06:07 AM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •