Rear derailleur mystery shift- Mtbr.com
Results 1 to 14 of 14
  1. #1
    mtbr member
    Reputation:
    Join Date
    May 2007
    Posts
    34

    Rear derailleur mystery shift

    I have a 2007 overseas made XCL. About once or twice a ride my rear derailleur shifts on it's own. It always happens on short technical climbs when the rear suspension is very active while in the middle chainring. I have 2007 XTR shifters and a 2007 XT rear derailleur everything is adjusted perfectly and the chain is not too long. As you probably know, Shimano rear deraileurs make contact with horst link bikes, hense the rubber bumper on the new derailleurs. My hunch is the rear derailleur is getting bumped as the suspension moves causing the problem. Any other ideas? I know the SRAM design does not make contact with the horst link so I was thinking of giving one of those a try.

    Mark

  2. #2
    mtbr member
    Reputation: dubjay's Avatar
    Join Date
    May 2004
    Posts
    786
    I wouldn't think it would be the derailleur in this case, unless you don't have much tension on the B-tension screw.

    Instead, check the cable routing and make sure none of it binds through the full suspension travel. One thing you can try doing is letting out all of the air from the shock and just cycle it through on the workstand.

  3. #3
    mtbr member
    Reputation: dubjay's Avatar
    Join Date
    May 2004
    Posts
    786
    Oh - if you do decide to change your derailleur, you should try a set of the new 2008 XT Shadow rear derailleurs. They're setback, similar to the SRAM ones, but then you wouldn't need to get new shifters.

  4. #4
    mtbr member
    Reputation: CHUMBAevo's Avatar
    Join Date
    Jul 2006
    Posts
    1,134

    ..

    Quote Originally Posted by dubjay
    Oh - if you do decide to change your derailleur, you should try a set of the new 2008 XT Shadow rear derailleurs. They're setback, similar to the SRAM ones, but then you wouldn't need to get new shifters.
    Agreed w/ Dubjay. The new XT Shadows have better positioning.
    Simple | Proven | Reliable

    http://chumbaracing.blogspot.com/

  5. #5
    mtbr member
    Reputation:
    Join Date
    Feb 2006
    Posts
    1,755
    I agree that it is probably not the derailleur. I have a Tracer which is essentially the same rear with a Shimano XTR and "ghost shifting" is not a problem. I suspect that it is the center/middle (near the seat tube) shifter housing area that is causing the problem. I have seen this before and it usually means that the center housing length is too short. Hope this helps.

  6. #6
    mtbr member
    Reputation:
    Join Date
    May 2007
    Posts
    34
    All:

    Thanks for the advice! Sounds like its probably a cable housing issue, I'll zero in on that. The new Shimano shadow derailleur looks pretty nice, does it really require a shifter upgrade?

    Mark

  7. #7
    mtbr member
    Reputation: dubjay's Avatar
    Join Date
    May 2004
    Posts
    786
    Quote Originally Posted by mad4mtnbike
    All:

    Thanks for the advice! Sounds like its probably a cable housing issue, I'll zero in on that. The new Shimano shadow derailleur looks pretty nice, does it really require a shifter upgrade?

    Mark
    You should be able to use your XTR shifters with that derailleur - no problem.

  8. #8

    Reputation:
    Join Date
    Apr 2007
    Posts
    208
    Wow you guy are fast I didn't even get to respond.

  9. #9
    Don't be a sheep
    Reputation:
    Join Date
    Sep 2004
    Posts
    3,422
    Quote Originally Posted by mad4mtnbike
    I have a 2007 overseas made XCL. About once or twice a ride my rear derailleur shifts on it's own. It always happens on short technical climbs when the rear suspension is very active while in the middle chainring. I have 2007 XTR shifters and a 2007 XT rear derailleur everything is adjusted perfectly and the chain is not too long. As you probably know, Shimano rear deraileurs make contact with horst link bikes, hense the rubber bumper on the new derailleurs. My hunch is the rear derailleur is getting bumped as the suspension moves causing the problem. Any other ideas? I know the SRAM design does not make contact with the horst link so I was thinking of giving one of those a try.

    Mark
    Your hunch is EXACTLY what is happening. I was able to watch mine do the same thing with the same derailluer. I have a new XT shadow derailluer coming in the mail ($86.00 shipped new off eBay) to solve this problem. I was going to switch to SRAM X.9 stuff but this option was cheaper and I've seen too many friends break SRAM derailluers.
    "Do not touch the trim"

  10. #10
    mtbr member
    Reputation:
    Join Date
    May 2007
    Posts
    34
    The older style XT derailleur was the problem. I player around with different cable housing lengths and the ghost shifting still occurred. Changed to a new XT shadow derailleur, no more ghost shifting! My PUSHED RP23 showed up today, hoping to try it out the weekend!

    Mark

  11. #11
    mtbr member
    Reputation: Scottandhisdog's Avatar
    Join Date
    Feb 2005
    Posts
    251

    Glad this thread existed

    I just ordered an XCL and was going to toss on my old sort of busted XT rear d, but then read this. Maybe I'll upgrade to the new Shadow RD.

    Anyone running dual controls on the XCL? I am contemplating getting that setup, because after dislocating my thumbs twice, trigger shifting sometimes hurts. I sound like a wuss, but it sucks when it happens.

  12. #12
    Older than I feel
    Reputation:
    Join Date
    Aug 2006
    Posts
    1,762
    Mark, keep us posted on the new XT and the PUSHed RP23.

    Scott, have you considered grip shifters? Personally I don't care for them, but they might help in your case.

  13. #13
    Trophy Husband
    Reputation: geolover's Avatar
    Join Date
    Nov 2005
    Posts
    3,011
    Quote Originally Posted by chucko58
    Scott, have you considered grip shifters? Personally I don't care for them, but they might help in your case.
    FWIW, I have grip shifters on my XCL. It's my first experience with them. I like them. There are many plusses and only a few minuses (sp?). Minuses being - Takes a little while to get used to them if you've been using triggers. Finding grips to use with them can be tricky...I'm using the stubby ODI Ruffians with no complaints.

    I don't hit my knees on triggers anymore. The front shifter has 10 positions, which means no more rubbing front deraileur anymore.

    I'd buy them again.

    Anyhoo, my unsolicited .02c.
    Extreme stationary biker.

  14. #14
    mtbr member
    Reputation:
    Join Date
    May 2007
    Posts
    34
    I've logged about 40 very technical miles on the new XT shadow derailleur. Still no ghost shifting and the performance has been flawless. No obvious shifting difference between old and new XT derailleur. I'm sure the fact that everything is nice and compact and close to the cassette will minimize derailleur replacements because of damage.

    Mark

Members who have read this thread: 0

Posting Permissions

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

THE SITE

ABOUT MTBR

VISIT US AT

© Copyright 2019 VerticalScope Inc. All rights reserved.