Brake disk runout question

pbassred
pbassred Posts: 208
edited March 2017 in MTB workshop & tech
I just fitted a brand new disk to a 2nd had wheel. Its not running true. I'm going to take the wheel off again to make sure the mounting face if clean. I have a dial gauge somewhere if I can find it.
How much wobble is too much?

Comments

  • swod1
    swod1 Posts: 1,639
    pbassred wrote:
    I just fitted a brand new disk to a 2nd had wheel. Its not running true. I'm going to take the wheel off again to make sure the mounting face if clean. I have a dial gauge somewhere if I can find it.
    How much wobble is too much?

    You Not tried a adjustable spanner to tweak the disc?

    Did you do the bolts up in a cross pattern as this will make sure the disc is on straight.
  • mattyfez
    mattyfez Posts: 638
    I'd first check the disk is true, lay it on a flat surface.
    Nothing wrong with bashing it straight if it's not true.

    However, you can have the impression of a bent disk from various other factors, worn pads, misaligned calipers, wheels not sat properly in the frame etc.
  • pbassred
    pbassred Posts: 208
    You Not tried a adjustable spanner to tweak the disc?
    Not until I know what is wrong.
    Did you do the bolts up in a cross pattern as this will make sure the disc is on straight.
    Always.

    I did clock it and found that its 0.2mm off. I've had it in and out of the bike twice and took care to seat it right each time. What I get is an intermittent rubbing. That says warped rather than misaligned. Its a used wheel but it seems to run true. The disk is a new Avid. I checked it with a straight edge.

    It might be time to consult the LBS.
  • JGTR
    JGTR Posts: 1,404
    Have you aligned calliper correctly?

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