Won't change to big ring on front

philsalliss
philsalliss Posts: 175
edited September 2014 in Workshop
Just collected my new bike today and fitted a chain catcher myself and front derailer now won't shift to big ring. Can someone give me a numpty guide to fox it so I can use it tommorow . Thanks

Comments

  • ElectronShepherd
    ElectronShepherd Posts: 227
    As you shift to the big ring, the cable pulls down, so part of the derailleur moves down. My guess would be that the cable clamp and arm are moving down and hitting the chain catcher, thus preventing the shift.

    Is the chain catcher mounted to the braze-on point, or does it clamp around the seat tube? If you have access to a camera, a couple of photos would probably help.
  • norvernrob
    norvernrob Posts: 1,448
    Assuming it's set at the right height, then it's probably just cable tension as that's what pulls the derailleur across.

    This is a good video for explaining it clearly.

    http://roadcyclinguk.com/how-to/mainten ... lleur.html
  • philsalliss
    philsalliss Posts: 175
    https://www.dropbox.com/s/jwmgowm0vkj2s1z/2014-09-09%2022.49.22.jpg?dl=0

    https://www.dropbox.com/s/ce2i3gneccikufn/2014-09-09%2022.48.58.jpg?dl=0

    I think it's the height that's wrong just not sure how to sort it. I really should have learnt by now not to fiddle with stuff I don't understand
  • trailflow
    trailflow Posts: 1,311
    If you have an inline barrel adjuster installed on the cable for the front derailler,you can add more cable tension by turning it outwards.

    If not , try loosening the cable clamp bolt. Then pull the cable tighter (a pair of pliers helps) and re-clamp and tighten the cable bolt.

    To adjust the height of the front derailleur you need to use the 'braze on' bolt (the bolt you fitted the chain catcher too). This needs to be done first. Before clamping the cable.

    The height looks ok to me but it could go a little lower.
  • philsalliss
    philsalliss Posts: 175
    Should have said its a braze on and the gears were fine before I cocked them up putting the chain catcher on. I had a ride round block to test and all was fine so I wouldn't think its anything to do with cables and so forth just simply position of derailer.

    I've given up and a friend who is a bike mechanic is hopefully nipping round later to sort it so I can go out. I really should learn not to fiddle
  • trailflow
    trailflow Posts: 1,311
    When you undo the braze on bolt the cable will loose its tension. Even if you push the derailleur back to the position it was before after fitting chain catcher. It still would not be the same tension as it was before. You would of added slack to the cable.
  • philsalliss
    philsalliss Posts: 175
    Thanks that makes sense actually. Didn't think of that
  • philsalliss
    philsalliss Posts: 175
    All sorted was derailer position and cabled adjustment

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