Rim rubbing brake pad



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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 .
 
P

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
 
C

Chris Zacho "Th

Guest
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
 
S

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
 
H

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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