Chain grinding off front derailleur.

Discussion in 'Bicycle Mechanics and Repairs' started by JaggyNI, 31 Jul 2012.

  1. Ok so I've looked up a few youtube videos/read some other threads on how to fix this problem. I've literally just spent 2/3 hours trying to sort it out to no avail. I know it's supposed to be "one of the most difficult adjustments" to make on a bike but this is taking the piss!

    I set the derailleur at the correct height, and then 2mm (which was what was recommended in a video) between the chain and the derailleur on the lowest front ring. The next step of the video was to adjust the high or low screws to move the derailleur in or out thus away from the chain and it doesn't grind.

    That is where my problem is. When I turn the screws either way I can't for the life of me see any movement whatsoever. Am I doing something wrong? Or is there something wrong with my bike? Anyone able to help me out here? If I need to provide some other info please let me know... newbie to fixing my own bike!

    If it's any use, the bike is a BTwin Triban 3. Hopefully someone's able to help me out.... I'm off to bed (with sore hands!) Thanks!
     
  2. PJ79LIZARD

    PJ79LIZARD Über Member

    Location:
    WEST MIDLANDS
    When you put the chain on the big ring at the front does the gear cable attached to the the front mech feel loose when you twang it with your fingers. It should feel quite taught. If it feels loose tighten the barrel adjuster on the frame to tighten it, turn it just a quarter of a turn each time. Then try adjusting the front mech with the limit screws again, see if you have any more joy.
     
  3. Rob3rt

    Rob3rt Man or Moose!

    Location:
    Manchester
    1st things 1st, in which gears does it grind? All of them or just some? This might be user error in use and not a set up problem. Before tinkering further please clarify, because no amount of adjusting will account for user error.

    Example case of user error that you may be experiencing is if you are using the big ring (front) to small ring (rear) or the opposite, the chain line will be appaling and it will grind against the front derailleur and also wear the cassette and chainrings, you should ideally use a different combination to get the same or similar ratio in order to save your bike the pain, but if you must use silly combinations, then at least utilise the trim feature on the front STI shifter to move the derailleur a bit and prevent the chain grinding there.
     
  4. PpPete

    PpPete Guru

    Location:
    Chandler's Ford
    The high and low screws dont move the derailleur much at all... they just limit the end points of motion of the derailleur, but you know that....if you were watching the right videos..
     
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