Rim rubbing brake pad

Discussion in 'Cycling Equipment' started by Richard, May 9, 2003.

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  1. Richard

    Richard Guest

    While holding the seat tube and holding the bike up, allowing the back wheel to spin. When using the
    brake calipers to close the gap between the brake shoes and the rim I stop closing the gap when the
    pads are touching the rim. When I widen the gap just a bit, somewhere on the rim, just a one spot,
    the pads rubs the rim and I can feel a slight vibration through the seat tube. No other portion rub
    the rim while spinning.

    Cannot see a bump or any deviation on the rim. IS the rim warp or What???

    The wheel is been trued twice .
     
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  2. Phil Holman

    Phil Holman Guest

    "Richard" <[email protected]> wrote in message
    news:[email protected]...
    > While holding the seat tube and holding the bike up, allowing the back wheel to spin. When using
    > the brake calipers to close the gap between the brake shoes and the rim I stop closing the gap
    > when the pads are touching the rim. When I widen the gap just a bit, somewhere on the rim, just a
    > one spot, the pads rubs the rim and I can feel a slight vibration through the seat tube. No other
    > portion rub the rim while spinning.
    >
    > Cannot see a bump or any deviation on the rim. IS the rim warp or What???
    >
    > The wheel is been trued twice .

    Check to see if this is at the rim joint (diagonally opposite the valve stem). The joint is often
    not as true as one would like depending on the quality of the wheel.

    Phil Holman
     
  3. Your wheel has gotten out of true. Since you haven't figured this out, I assume you do not know how
    to true it yourself.

    Bring it to a bike shop and tell them you need your wheels properly tensioned and trued.

    May you have the wind at your back. And a really low gear for the hills! Chris

    Chris'Z Corner "The Website for the Common Bicyclist": http://www.geocities.com/czcorner
     
  4. Suzy Jackson

    Suzy Jackson Guest

    "Richard" <[email protected]> wrote in message
    news:[email protected]...
    > While holding the seat tube and holding the bike up, allowing the back wheel to spin. When using
    > the brake calipers to close the gap between the brake shoes and the rim I stop closing the gap
    > when the pads are touching the rim. When I widen the gap just a bit, somewhere on the rim, just a
    > one spot, the pads rubs the rim and I can feel a slight vibration through the seat tube. No other
    > portion rub the rim while spinning.

    This is a common, yet all to often misunderstood problem.

    Basically what is happening is that your brake pads are frightened of the valve stem. As the valve
    stem approaches, they try their best to get away, and push themselves back against the pull of the
    cable. The cable has a little springiness in it, so once the valve stem has passed by, and the brake
    pads relax, they bounce in and touch the rim. Often this comes about as a result of a young brake
    being misadjusted and having its pads dive under the rim and come much too close to the valve stem.
    Such a brake may display this behaviour for many years.

    I'm afraid all that can be done to solve the problem is proper counselling by a qualified bicycle
    counsellor. He or she will set up your brakes with care and tenderness, and reassure the pads that
    there is no danger of them being clobbered by an errant valve stem. Once they've relaxed a bit, the
    problem shouldn't resurface.

    I hope that's thrown some light on the problem.

    Regards,

    Suzy

    --
    ---
    Suzy Jackson [email protected] http://www.suzyj.net
     
  5. Hawke

    Hawke Guest

    "Suzy Jackson" <[email protected]> wrote in message
    news:[email protected]...
    > "Richard" <[email protected]> wrote in message
    > news:[email protected]...
    > > While holding the seat tube and holding the bike up, allowing the back wheel to spin. When using
    > > the brake calipers to close the gap between the brake shoes and the rim I stop closing the gap
    > > when the pads are touching the rim. When I widen the gap just a bit, somewhere on the rim, just
    > > a one spot, the pads rubs the rim and I can feel a slight vibration through the seat tube. No
    > > other portion rub the rim while spinning.
    >
    > This is a common, yet all to often misunderstood problem.
    >
    > Basically what is happening is that your brake pads are frightened of the valve stem. As the valve
    > stem approaches, they try their best to get
    away,
    > and push themselves back against the pull of the cable. The cable has a little springiness in it,
    > so once the valve stem has passed by, and the brake pads relax, they bounce in and touch the rim.
    > Often this comes
    about
    > as a result of a young brake being misadjusted and having its pads dive under the rim and come
    > much too close to the valve stem. Such a brake may display this behaviour for many years.
    >
    > I'm afraid all that can be done to solve the problem is proper counselling by a qualified bicycle
    > counsellor. He or she will set up your brakes with care and tenderness, and reassure the pads that
    > there is no danger of them being clobbered by an errant valve stem. Once they've relaxed a bit,
    > the problem shouldn't resurface.
    >
    > I hope that's thrown some light on the problem.
    >
    > Regards,
    >
    > Suzy

    This be true!

    Hawke
     
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