Judder when using my front brake? Help needed pls.

manc_ian
manc_ian Posts: 166
edited December 2007 in MTB workshop & tech
Hello. I have a Giant XTC SX with the MPH Brakes. I have upgraded the standard rotor to a 180 Aztec Rotor (same size as original).

During my last 3 or 4 rides ive noticed a lot of judder from the front rotor (like a back and forth motion in the forks). It only happens when braking on a fairly fast decent. Ive checked everything i could think of to see if anything is lose but all seems fine. My pads should be ok aswell.

Can anyone give me an idea what this might be and how i can resolve the annoying problem?

Cheers

Ian

Comments

  • manc_ian
    manc_ian Posts: 166
    Ive just noticed that when i apply the brakes the rotor bends slighty to one side. Could this be the problem and if so how do i centre the rotor?
  • chilledsandwich
    chilledsandwich Posts: 128
    To centre the rotor simply put shims between the caliper and the disc mounts to get it to the correct distance out. http://www.chainreactioncycles.com/Models.aspx?ModelID=356

    OR depending on which versions you have you might be able to loosen the two screws that go from the caliper into the mount adapter to move the caliper left and right.

    Don't know about the juddering though, sorry. Have you refitted the original disc to see if you still have the problem?? If not, try it, it may be the new disc
  • dave_hill
    dave_hill Posts: 3,877
    Juddering can be caused by several things -

    If you haven't bedded the disc/pads in properly, this may have caused the rotor to overheat, warping it. If this is the case, there's nothing you can do - the rotor is beyond saving.

    The pads may be glazed - take them out and rub the braking surfaces lightly with a piece of medium emery cloth or wet-and-dry paper (place it on a flat surface and rub the pad on it rather than tryign to hold the pad in one hand and sand with the other).

    Your fork bushes may be worn, allowing the stanchions to rock in the lowers.

    Your headset may be loose.
    Give a home to a retired Greyhound. Tia Greyhound Rescue
    Help for Heroes
    JayPic
  • BigR
    BigR Posts: 35
    As Dave says - most likely your headset is loose. I would slacken of the stem and cap and then re-tension the headset. I have had a similar problem which only took 5 mins to sort.

    BigR
  • boingboing12345
    boingboing12345 Posts: 58
    If your disk is moving under braking you need to centre it as this will cause the judder. My old bike had hayes sole and if the pads were not coming together square it felt like the headset was really slack, you could see the disk being pushed off centre which caused the judder.

Categories