Front Derailleur skewiff!

quad121m4QvXvk_
quad121m4QvXvk_ Posts: 14
in MTB general
Good afternoon to you all
I have a SRAM X0 3x10 front derailleur which I purchased secondhand.
I’ve set it up and it works very well over than that the tension of the cable is pulling on the mech and making the cage ‘move’ further off the chainrings ?
Do you need to fit some sort of rubber ‘sleeve ‘ between the mech and the frame to stop it moving?
I’m sorry for the bad description

Comments

  • me-109
    me-109 Posts: 1,915
    The cage will swing up as it moves outwards. Do you mean the mech is sliding down the frame as you add tension into the cable?
  • quad121m4QvXvk_
    quad121m4QvXvk_ Posts: 14
    Hi, I’ve tightened the clamp as much as I dare. The top of the cage is at the correct gapping of around 2-3mm and when I set the bottom part of the cage to the same measurements (2-3mm). After a short period of time this part of the cage moves slightly away from the chainrings, making the gap more like 5-6mm.
  • webboo
    webboo Posts: 6,087
    Is it the right size for your frame.
  • quad121m4QvXvk_
    quad121m4QvXvk_ Posts: 14
    It’s a 34.9mm seat tube and it says it covers 66-69 degrees tube angles. It does state 34.9mm on it.
    Surely if this covers these angles there’s going to be movement to accommodate but I’m not sure how to stop this from happening
  • steve_sordy
    steve_sordy Posts: 2,453
    edited January 2022
    Has the thread worn where the clamp screw goes? That means that the clamping force is reduced.
    Has the band that you are clamping bent and reduced the gap that the screw is tightening upon? This will reduce the clamping force, even if you tighten the screw so much that the clamping faces touch.

    If all else fails and you cannot see what the problem is, you have two options:
    1) Take it your LBS.
    2) Put some inner tube under the clamp to increase the gap that the screw is closing.

    Edit: Just as I pressed "Save Post" I thought of something else.

    The clamp could be OK, but it is another part of the mech that is worn or loose. Put a mark on the frame and the clamping band to see if anything moves. You will then know for sure whether it is the clamp or the mech. Proceed from there.
  • quad121m4QvXvk_
    quad121m4QvXvk_ Posts: 14
    Thank you for the ideas.
    The inner tune idea seems to be a good idea as it may stop the mech moving on the tube!
    I’ve checked the clamp and associated bolt etc and they all seem fine.
    The rest of the mech seems very solid at all the moving joints with no unwanted’play’.
  • webboo
    webboo Posts: 6,087
    Is it the right mech for your shifters.
  • quad121m4QvXvk_
    quad121m4QvXvk_ Posts: 14
    The shifters are also sram X0s

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