Can't get front derailler to shift to big chainring while ri

krushgroove
krushgroove Posts: 27
edited June 2008 in MTB workshop & tech
I've successfully adjusted my rear and front deraillers using the Park tools website tutorials, which is great, however after getting everything shifting smoothly while the bike is on its mini-stand and I'm not on it, I can't get it to shift to the big chainring while I'm actually riding it.

I've had a play with moving the H screw and the cable tension but I always seem to goof it up and have to practically restart the whole front derailler adjustment procedure, so I was wondering if someone can tell me what I need to adjust? It seems to me that it's just one thing that needs to be fiddled with but I'm a bit lost...I'd appreciate any help!
'99 Giant ATX 890
'?? Raliegh something-or-other, commuter
Trying to keep the rubber side down!

Comments

  • artillerydave
    artillerydave Posts: 715
    you need to adjust the limit screws high and low to ensure the mech can reach all the rings but not overshift, then set the cable tension. also ensore the mech is pefrectly parrallel to the rings. Parktools would be best for descriptions. or a friend who is in the know.
  • boyfriday
    boyfriday Posts: 103
    I had a similar problem and made all the adjustments recommended on the forums, but still couldn't get the front mech to shift to the big ring - when the lever was compressed, the mech was taking its position required for the big ring but just wasn't catching and immediately upon releasing the lever the chain was popping back into the small chainring.

    Turns out the actual gear cable had not been housed properly by the LBS and had came loose and jammed in the lever - haven't had it repaired yet, but will hopefully get it done this weekend.

    If the suggestions put forward by others don't solve your problem, this might be it.
  • nicklouse
    nicklouse Posts: 50,675
    what is the bike?

    Pics?
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • markwatton
    markwatton Posts: 23
    Where does your workstand clamp the bike? You may have inadvertantly had the clamp against the cable, when you take the bike off the stand the cable looses some tension and hence will not shift across to the big ring.
  • krushgroove
    krushgroove Posts: 27
    Hi, thanks very much for the replies!

    The bike is the same as in my signature, just an old MTB I got off eBay...I'm trying to scrounge up a more suitable commuter so I can keep this one dirt-only :) The workstand is just a small one that hangs the bike on the chainstay and seatstay, it doesn't clamp onto the downtube or top tube.

    I'll try again with the H screw, but I'm not sure how to set the cable tension properly. What direction do I turn the barrel adjuster to tighten or loosen the cable? Or should I just loosen/tighten the cable at the derailer end?
    '99 Giant ATX 890
    '?? Raliegh something-or-other, commuter
    Trying to keep the rubber side down!
  • supersonic
    supersonic Posts: 82,708
    Make sure all the cable slack is puleed through when in the low gear, and re fasten the cable. Turn the barrel adjuster at the shifter anticlockwise to add tension.
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  • krushgroove
    krushgroove Posts: 27
    Ta very much :) It's on the rack here at work and I'll give it a go at lunchtime
    '99 Giant ATX 890
    '?? Raliegh something-or-other, commuter
    Trying to keep the rubber side down!

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