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  1. #1
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    brake lever pulsing - what's causing it????

    Replaced rotor, pads, and adapter. Same problem.

    Getting pulsing through the brake lever once every wheel rotation. If I keep constant pressure on the brake lever, it feels like the brake is going on/off/on/off/on/off

    Any ideas? Rotor looks dead straight, pads aligned. There is a slight vertical movement (about a mm or so).

    The ring on the hub that the rotor sits against appears to have cracked off*. Wondering therefore if it is the slight vertical movement that is causing this.

    Hub: Hope Pro 2
    Brakes: 2010 SLX
    Rotor: Superstar 'VIBE' 180mm

    * wondering if the rotor is machined with too small a gap, or maybe the ring on the hub is too large. Assume there is a standard size it's supposed to be.

    The ring that's cracked off is the one on this pic, which runs around the edge of the QR adapter:

  2. #2
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    Did you bed in the new pads and rotors properly?

  3. #3
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    As well as I can, I can't maintain hard braking for any period due to the on off on off on off

    I should add that I had this issue on my old rotor and pads (hence replacing them all).

    This is why i am now suspecting it may be down to the vertical movement which is possibly due to the broken lip on the hub (which the rotor may well have caused if it were machined incorrectly).
    Last edited by retro83; 03-14-2012 at 07:11 AM.

  4. #4
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    Are you talking about the ring with the little teeth on it that bite into the drop out? If you have any hub movement in the drop out, you will certainly notice it braking. You can also try bleeding the brakes. On my motorcycle, I had a similar problem with my front brake which turned out to be a little pocket of air bubbles trapped in the master cylinder/lever.

    Whenever I clean my pads and rotors, I like to heat them up with a butane torch. This usually burns off any trace of contaminates. I do the same thing before installing new pads or rotors.

    Good luck.

  5. #5
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    Quote Originally Posted by Erotomania View Post
    Are you talking about the ring with the little teeth on it that bite into the drop out? If you have any hub movement in the drop out, you will certainly notice it braking. You can also try bleeding the brakes. On my motorcycle, I had a similar problem with my front brake which turned out to be a little pocket of air bubbles trapped in the master cylinder/lever.
    No, imagine that black bit was removed you'd just have a little lip there which normally the rotor rests against. Except on my hub, half of that bit has snapped off some how. I wondered if that is what normally centres the rotor on the hub (and would therefore explain the vertical movement seen at the caliper)

    I can bleed it again, but not sure how air in the lines could cause pulsing as such

  6. #6
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    Maybe this will explain better:

    Undamaged side:


    Side which i think has possibly been damaged by the rotor:


    Can only think rotor is drilled slightly off centre or something.

  7. #7
    g3h6o3
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    Pulsing is most commonly caused by a rotor that's out of true, and I mean badly out of true, like you hit a rock or something.

    Is your rotor straight? You mention a vertical movement...
    Check out my SportTracks plugins for some training aid software.

  8. #8
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    Listen!

    Quote Originally Posted by PissedOffCil View Post
    Pulsing is most commonly caused by a rotor that's out of true, and I mean badly out of true, like you hit a rock or something.

    Is your rotor straight? You mention a vertical movement...

    Yeah, perfectly straight side to side, with about a 1-2 mm wobble vertically.

    Can'd detect any thickness changes with my el-cheapo digital calipers .

    Starting to thing either the hub has somehow gone on the wonk, or the rotor is drilled off centre.

  9. #9
    g3h6o3
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    In theory the vertical wobble could cause your pad to "oscillate" because it goes off the braking track and then back on, causing a wobble...

    Does the wobble area match the pulsing?
    Check out my SportTracks plugins for some training aid software.

  10. #10
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    Rotor thickness variation

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