weight shift from out of saddle pedaling causes disk brakes to rub pads

Discussion in 'Mountain Bikes' started by horizon, Mar 26, 2007.

  1. horizon

    horizon New Member

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    when out of the saddle and bringing the bike side to side i hear the gentle whisper of a pad rubbing. it should be happening front and back.
    bringing my pads out creates alot of brake lever play. does everyone with disks put up with alot of play? i don't see how spoke tension would help b/c the disk is connected to the hub.

    wheels - mavic crosslink
    brakes - 8 inch avid somethings, good ones, mechanical

    any solutions? i'm sure this has happened to many.
     
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  2. dabac

    dabac Well-Known Member

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    Are you annoyed at the sound or at the lost energy? Disc brakes haven't a lot of clearance, so it doesn't take much for them to rub. If you're worried about the lost energy why not lift a wheel off the ground, spin it up, apply brakes until you've recreated the sound, see what it actually does to slow the wheel down.

    I don't think you should blame either your wheels or your brakes for this, I think it's the frame/fork that's flexing. It has far more give than the comparatively solid hub / disc assembly.
    Tighter/ better QR's might help some, but that's assuming the ones you have needs improving.
     
  3. horizon

    horizon New Member

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    the lost energy and brake wear is what i'm annoyed about.

    i'll post a reply when i try the advice above.
     
  4. davebee

    davebee New Member

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    The brake wear as a result of the pads "whispering" against the rotor is negligible. The noise can be irritating but you get used to it and soon stop hearing it.

    The loss of energy is also negligible. As mentioned above the cause is because of the very small clearence between pad and rotor. What fork are you using? All but the very best forks will tend to have some flex in them.
     
  5. bigpedaler

    bigpedaler New Member

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    there's also the issue of trueness of the rotor -- even if you get it perfect, it won't stay perfect.

    i have the same thing happening, f&r both -- dakar xlt frame, nixon fork. i just deal w/ it. i have more energy loss from the bearing drag in my outboard BB. brake wear is SOOOOOOO negligible, the rotors would rust before the pads wore out from this.
     
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