Drivetrain help please

bobcheese
bobcheese Posts: 343
edited December 2012 in MTB workshop & tech
Guys, need some help. I'm setting up my new drive train (SLX 10sp double) with SLX rear and shifters. Trying to sort the rear mech. Got the lower jockey wheel in line using limit screws but when I connect the cable and try shifting I get a problem. Basically I can shift to the lowest gear but the upper jockey wheel stops the chain moving to the upper cog. Even with the b tension screwed all the way in. So I am wondering if the chain is too long and not putting enough tension on the mech so it is in the correct place. I set the chain length as large ring - large cog + 2 links.

Any thoughts?
viewtopic.php?f=10017&t=12890922

Comments

  • The Rookie
    The Rookie Posts: 27,812
    Ignore the lower jockey wheel, it's the upper's postition that counts.

    Have you sized the chain as per manufacturers instructions/parktools/sheldon brown (all give the same length).

    'upper cog' being which one?
    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.
  • bobcheese
    bobcheese Posts: 343
    So when I put the shifter to the lowest gear the chain should move to the largest cog on the rear cassette but the upper jockey wheel gets in the way and won't allow the shift. Like I said I think the chain length is set as large cog to large ring (not through mech) + 2 links
    viewtopic.php?f=10017&t=12890922
  • The Rookie
    The Rookie Posts: 27,812
    OK either you have the wrong mech (not able to accomodate the largest sprocket) or the chain is too SHORT (that will pull the mech forward and the upper jockey into the sprocket - don't ask me how I know this for sure, I just do ;-) ) or the B-screw needs winding in even more (pushing the mech back an the upper jockey down).

    How stretched forward is the lower part of the mech when this happens (photo's would help).

    Does this happen with the chain on both front rings or only one, if so the larger or the smaller?
    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.
  • Chunkers1980
    Chunkers1980 Posts: 8,035
    Check the mech is screwed on correctly and the bump is in the correct place.
  • bobcheese
    bobcheese Posts: 343
    This
    Chunkers1980 wrote:
    Check the mech is screwed on correctly and the bump is in the correct place.

    Thanks for the help :)
    viewtopic.php?f=10017&t=12890922

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