Unable to shift to outside ring on XT

PuttyKnees
PuttyKnees Posts: 381
edited May 2014 in MTB workshop & tech
I'm currently running an XTR front mech with an XT M785 2x10 chainset and I'm finding that the front mech doesn't have the reach to move the chain on to the big ring, even when the limit is fully out. I first wondered whether I had the correct number of spacers on the BB, but this seems right (2x2.5mm on the drive side, 1x2.5mm on the non-drive). Is there a compatibility issue with the xtr front mech and xt chainset? Or should I move one of the spacers to the non-drive to move the chainset in a bit? Or have I missed something else?

Comments

  • Ouija
    Ouija Posts: 1,386
    Depends on the frame. If you've got a frame with a BB shell that's 73mm wide you don't need any spacers at all.
  • jimothy78
    jimothy78 Posts: 1,407
    Ouija wrote:
    Depends on the frame. If you've got a frame with a BB shell that's 73mm wide you don't need any spacers at all.

    ^Wrong - you still need one on the driveside.

    Puttyknees - what's the model number of the mech, and is it band-on, bb mount or direct mount?
  • PuttyKnees
    PuttyKnees Posts: 381
    Well, I thought it was 68mm, but now I'm doubting myself. The mech is a band on, but I'm not sure what the exact model number is as I got it 2nd hand. I will check the BB width and mech code tonight to make sure.
  • jimothy78
    jimothy78 Posts: 1,407
    PuttyKnees wrote:
    The mech is a band on, but I'm not sure what the exact model number is as I got it 2nd hand.
    it'll be on the cage or band of the derailleur somewhere.

    While you're at it, try disconnecting the cable to ascertain if it's that which is preventing the cage of the derailleur moving far enough out, or something else.
  • The Rookie
    The Rookie Posts: 27,812
    Be worth measuring the chainline (centreline of frame to midway between the 2 rings) should be 47.5 or 50mm, more could be an issue.
    Currently riding a Whyte T130C, X0 drivetrain, Magura Trail brakes converted to mixed wheel size (homebuilt wheels) with 140mm Fox 34 Rhythm and RP23 suspension. 12.2Kg.
  • PuttyKnees
    PuttyKnees Posts: 381
    Thanks for the tips. It's a 68mm and the centreline distance looks fine. I did however locate the problem - probably my own incompetence. I noticed on further inspection that the mech was not parallel to the chainrings and have sorted that and redone the cables it's all fine now.

Categories