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Main
Date: 24 May 2007 17:14:58
From:
Subject: what causes 1 brake shoe to stay on rim?
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have center pull brakes and this is a problem i've seen from time to
time in bikes i owned. i depress and release the brakes, this time on
the front wheel, and one shoe stays on the rim.
so frustrating! do i have to take the housing apart and replace the
spring?
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Date: 27 May 2007 05:38:15
From: Mike Jacoubowsky
Subject: Re: what causes 1 brake shoe to stay on rim?
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> have center pull brakes and this is a problem i've seen from time to
> time in bikes i owned. i depress and release the brakes, this time on
> the front wheel, and one shoe stays on the rim.
>
> so frustrating! do i have to take the housing apart and replace the
> spring?
It might not be the spring or even the brake itself, but rather a
severely-worn rim that now has a lip near the top of it (sometimes the pads
themselves can also be worn in such a way that they sort of hook into the
rim). Brake pads will sometimes catch on such lips and not want to
retract.Generally this only occurs when you're not actually riding the bike.
--Mike-- Chain Reaction Bicycles
www.ChainReactionBicycles.com
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Date: 25 May 2007 23:51:45
From: A Muzi
Subject: Re: what causes 1 brake shoe to stay on rim?
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tariq.1.rahim@spamgourmet.com wrote:
> have center pull brakes and this is a problem i've seen from time to
> time in bikes i owned. i depress and release the brakes, this time on
> the front wheel, and one shoe stays on the rim.
> so frustrating! do i have to take the housing apart and replace the
> spring?
Center wheel in fork first. Lubricate the centerbolt thread, torque
properly then move the bridge (not the arms) it will stay centered.
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971
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Date: 26 May 2007 17:21:35
From: Bob Chambers
Subject: Re: what causes 1 brake shoe to stay on rim?
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A Muzi wrote:
> tariq.1.rahim@spamgourmet.com wrote:
>> have center pull brakes and this is a problem i've seen from time to
>> time in bikes i owned. i depress and release the brakes, this time on
>> the front wheel, and one shoe stays on the rim.
>> so frustrating! do i have to take the housing apart and replace the
>> spring?
>
> Center wheel in fork first. Lubricate the centerbolt thread, torque
> properly then move the bridge (not the arms) it will stay centered.
>
Same for brakes on my MTB, except they are sidepull. Every time I
remove & replace the front wheel. the brakes are in a different spot and
the blocks are usually rubbing - always need adjustment of the springs.
What gives?
Bob C
--
Posted via a free Usenet account from http://www.teranews.com
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Date: 26 May 2007 09:25:48
From: Lou Holtman
Subject: Re: what causes 1 brake shoe to stay on rim?
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Bob Chambers wrote:
> A Muzi wrote:
>> tariq.1.rahim@spamgourmet.com wrote:
>>> have center pull brakes and this is a problem i've seen from time to
>>> time in bikes i owned. i depress and release the brakes, this time on
>>> the front wheel, and one shoe stays on the rim.
>>> so frustrating! do i have to take the housing apart and replace the
>>> spring?
>>
>> Center wheel in fork first. Lubricate the centerbolt thread, torque
>> properly then move the bridge (not the arms) it will stay centered.
>>
>
> Same for brakes on my MTB, except they are sidepull. Every time I
> remove & replace the front wheel. the brakes are in a different spot and
> the blocks are usually rubbing - always need adjustment of the springs.
> What gives?
> Bob C
>
Friction in the pivots.
Lou
--
Posted by news://news.nb.nu (http://www.nb.nu)
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Date: 26 May 2007 10:09:34
From: A Muzi
Subject: Re: what causes 1 brake shoe to stay on rim?
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>>> tariq.1.rahim@spamgourmet.com wrote:
>>>> have center pull brakes and this is a problem i've seen from time to
>>>> time in bikes i owned. i depress and release the brakes, this time on
>>>> the front wheel, and one shoe stays on the rim.
>>>> so frustrating! do i have to take the housing apart and replace the
>>>> spring?
>> A Muzi wrote:
>>> Center wheel in fork first. Lubricate the centerbolt thread, torque
>>> properly then move the bridge (not the arms) it will stay centered.
>Bob Chambers wrote:
>> Same for brakes on my MTB, except they are sidepull. Every time I
>> remove & replace the front wheel. the brakes are in a different spot
>> and the blocks are usually rubbing - always need adjustment of the
>> springs. What gives?
Lou Holtman wrote:
> Friction in the pivots.
That's possible, but more likely on a cantilever. Some cantilevers pivot
on the frame's boss. Remove brake assembly (one side at a time!), emery
post and sleeve, then lubricate well on installation.
Other cantilevers, like linear brakes, have an inner sleeve which stays
in place; a bronze sleeve in the arm pivots on the stationary steel
sleeve. Those are harder to deal with when corroded but the effort pays
well. You'll need a small press to separate them, emery all surfaces
then lubricate well on installation
Sidepulls benefit from oil on all mating surfaces including the end of
the spring where it slides on the arm's peg (In Jobst's pithy analysis,
'cosine error'). Like classic centerpulls, the arms 'float' on the
spring(s) so the centering mechanism is the position of the spring slot
in the centerbolt. Merely moving the arm is futile; the bolt's attitude
to the horizontal must be adjusted. Better sidepulls provide wrench
flats to achieve that; They are easily added with a file. Later Modolo
style centerbolts and copies (Shimano) offer a broached end socket for
an allen key.
As in all brake centering difficulties, slip your fingers aside the tire
or rim on both sides simultaneously before touching the brake itself.
More often than not the wheel is to one side.
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971
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Date: 25 May 2007 09:55:06
From: jim beam
Subject: Re: what causes 1 brake shoe to stay on rim?
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tariq.1.rahim@spamgourmet.com wrote:
> have center pull brakes and this is a problem i've seen from time to
> time in bikes i owned. i depress and release the brakes, this time on
> the front wheel, and one shoe stays on the rim.
>
> so frustrating! do i have to take the housing apart and replace the
> spring?
>
no, simply center the caliper correctly. there's usually a slot in the
pivot that allows a thin wrench to be used for this job.
or it's the wheel not positioned correctly.
either way, real simple.
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Date: 24 May 2007 17:33:29
From: Hank Wirtz
Subject: Re: what causes 1 brake shoe to stay on rim?
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On May 24, 5:14 pm, tariq.1.ra...@spamgourmet.com wrote:
> have center pull brakes and this is a problem i've seen from time to
> time in bikes i owned. i depress and release the brakes, this time on
> the front wheel, and one shoe stays on the rim.
>
> so frustrating! do i have to take the housing apart and replace the
> spring?
First, I'd make sure that the caliper is cenetered, if it's a
centerpull caliper brake. If it's already centered, you might want to
lube the pivots.
If it's a centerpull cantilever, at least one side's spring should be
adjustable. Increase the tension on the pad that's sticking.
Another problem can come on centerpull cantilevers if you have a link
wire, and the guide tube for for the main cable becomes compressed.
One half of the mechanism will have more mechanical advantage, and can
cause pull imbalance. You can replace the guide tube with some cable
housing, or replace the link wire with a traditional straddle cable
and yoke.
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