Front Mech Indexing Problems

Low Down And Dirty
Low Down And Dirty Posts: 35
edited February 2012 in MTB workshop & tech
Firstly many apologies if this has already been covered somewhere, did have a search but couldn't find anything.

I am having problems with the indexing of my front derailleur.

I have a Shimano XT front mech and SRAM X9 trigger.

It was shifting perfectly until a few weeks ago when I renewed the inner and outer cabling. I have run out of things to try. It sits perfectly on the lower adjustment screw and likewise on the high adjustment screw, when shifting up it works flawlessly shifting from small, to mid, to large, but when shifting down from the large chainring it just jumps straight to the small one, hit the lever and straight to the middle ring again, the triggers look ok and are well (but not over) lubed, cable routing seems fine, mech works fine, I really don't know what to try next, and any help would be gratefully received.

Andy

Comments

  • nicklouse
    nicklouse Posts: 50,673
    Stops and tension are no correct.

    Start agin with less tension.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • Low Down And Dirty
    Low Down And Dirty Posts: 35
    Well to much tension was my first thought, but I have let it off so much that the cable is actually completely slack when on the small ring.
  • nicklouse
    nicklouse Posts: 50,673
    Low Down And Dirty wrote:
    Well to much tension was my first thought, but I have let it off so much that the cable is actually completely slack when on the small ring.
    And that gives the above results? If yes then your stops are wrong. Wind the upper one right out so it does nothing and just work with tension and the lower stop. Then when it all works fine turn in th top screw to stop any over shift.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • Low Down And Dirty
    Low Down And Dirty Posts: 35
    right will try that, been pissing me off since I changed the cables but I can not put up with it any longer, the only way I can get it to shift to the mid ring is to hold the tension of the mech by hand press the trigger and then let go of of the mech. Really appreciate the input.
  • Low Down And Dirty
    Low Down And Dirty Posts: 35
    Managed to get the shifting better after the last post, but was never perfect, I found the problem today when I went out and my triggers fell to bits, the bolt holding the upshift trigger must have worked itself a little loose and today worked itself loose enough to completely fail. After a trackside bodge to carry on my ride. I got home then much swearing and fiddling with springs and little pins later I got it back together and is now working lovely.

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