Rims rubbing brakes while cornering

[Bugbear]

Is this something I should be concerned about?

When I take corners at a not too outrageous speed, say a 90 degree bend
at about 30km/h (eg negotiating a typical street intersection), I can
hear my rims rubbing against the brake pads (don't know if it's front
or back). Once I straighten up, the rubbing stops.

Is this a sign that I have set my brake pads too close to the rims?

 

[Gary Jacobson]

"Bugbear" <[email protected]> wrote in message
news:[email protected]...
> Is this something I should be concerned about?
>
> When I take corners at a not too outrageous speed, say a 90 degree bend
> at about 30km/h (eg negotiating a typical street intersection), I can
> hear my rims rubbing against the brake pads (don't know if it's front
> or back). Once I straighten up, the rubbing stops.
>
> Is this a sign that I have set my brake pads too close to the rims?

Could be.

But does it happen on both left and right turns?
Is the inner brake cable closing the calipers because the housing isn't long
enough to remain unbound when you turn?

Gary Jacobson
Rosendale, NY

 

[Bugbear]

Gary Jacobson wrote:
> Could be.
>
> But does it happen on both left and right turns?

You know I've never taken notice whether it is a left or right turn
only thing. I'll check it out going home this arvo.

 

[Donga]

Bugbear wrote:
> Is this something I should be concerned about?
>
> When I take corners at a not too outrageous speed, say a 90 degree bend
> at about 30km/h (eg negotiating a typical street intersection), I can
> hear my rims rubbing against the brake pads (don't know if it's front
> or back). Once I straighten up, the rubbing stops.
>
> Is this a sign that I have set my brake pads too close to the rims?

If you hold the tire (when stationary!!) and try to force it sideways
in either direction, is there play at the hub, or does the rim move
from slack spokes?

Donga

 

[Werehatrack]

On 22 Jan 2007 19:34:17 -0800, "Bugbear" <[email protected]> may
have said:

>Is this something I should be concerned about?
>
>When I take corners at a not too outrageous speed, say a 90 degree bend
>at about 30km/h (eg negotiating a typical street intersection), I can
>hear my rims rubbing against the brake pads (don't know if it's front
>or back). Once I straighten up, the rubbing stops.
>
>Is this a sign that I have set my brake pads too close to the rims?

Might be a wheel a bit out of true if the rub is intermittent, might
be a wheel bearing that's a trifle loose or worn, could be an early
failure in a frame member that's flexing but hasn't cracked through
yet, it could be a bent axle on the rear, and yes, it could be that
the pads are a trifle too close to the rims. And it's also possible
that the bike's just got flexy components that are allowing this to
happen. If you check all the basics and find nothing needing
attention, then the latter factor is a probable explanation.


--
My email address is antispammed; pull WEEDS if replying via e-mail.
Typoes are not a bug, they're a feature.
Words processed in a facility that contains nuts.

 

[Phil, Non-Squid]

Werehatrack wrote:
> On 22 Jan 2007 19:34:17 -0800, "Bugbear" <[email protected]> may
> have said:
>
>> Is this something I should be concerned about?
>>
>> When I take corners at a not too outrageous speed, say a 90 degree
>> bend at about 30km/h (eg negotiating a typical street intersection),
>> I can hear my rims rubbing against the brake pads (don't know if
>> it's front or back). Once I straighten up, the rubbing stops.
>>
>> Is this a sign that I have set my brake pads too close to the rims?
>
> Might be a wheel a bit out of true if the rub is intermittent, might
> be a wheel bearing that's a trifle loose or worn, could be an early
> failure in a frame member that's flexing but hasn't cracked through

There is the possibility of it being a cracked fork, too.
--
Phil

 

[ddog]

Or a quick release not holding tightly.

 

[Qui si parla Campagnolo]

ddog wrote:
> Or a quick release not holding tightly.

As from all the great suggestions, it shouldn't be happening, for
whatever reason.

 

[ddog]

Qui si parla Campagnolo wrote:
> ddog wrote:
> > Or a quick release not holding tightly.
>
> As from all the great suggestions, it shouldn't be happening, for
> whatever reason.

Well, if its down to speculation, I'd say loose tolerance Chinese hub
bearings.

 

[[email protected]]

Peter Chisholm writes:

>> Or a quick release not holding tightly.

> As from all the great suggestions, it shouldn't be happening, for
> whatever reason.

....and beyond that, there are no side forces on the wheel from
cornering, so what is this another troll?

Jobst Brandt

 

[ddog]

[email protected] wrote:
> Peter Chisholm writes:
>
> >> Or a quick release not holding tightly.
>
> > As from all the great suggestions, it shouldn't be happening, for
> > whatever reason.
>
> ...and beyond that, there are no side forces on the wheel from
> cornering, so what is this another troll?
>
> Jobst Brandt

That would depend on if you are leaning with body english to keep from
hitting pedal
on ground, or are in optimum straight positions non pedalling. I now
you go downhill
down Alps for miles straight, so are just holding on for life and
optimizing with no pedalling. I think
most bikers however pedal and will have tangental angle forces on their
bearings if they
are constant spinners using body english so they don't hit pedals on
ground, plus the effect of pedalling will also rock the bearings in
corners. So not only that but you have an additional centriputal forces
on wheels in corners to exagerate the effect. Is that a trick question?

 

[Werehatrack]

On 23 Jan 2007 18:05:46 GMT, [email protected] may have
said:

>Peter Chisholm writes:
>
>>> Or a quick release not holding tightly.
>
>> As from all the great suggestions, it shouldn't be happening, for
>> whatever reason.
>
>...and beyond that, there are no side forces on the wheel from
>cornering, so what is this another troll?

Some will lean off the inside of the bike when cornering, for a
variety of personal reasons, which can put side forces on the wheel.
(Think of the tactics often employed by motorcycle racers; I have seen
lots of bicyclists doing the same thing to one extent or another,
regardless of how ill-advised it might be.) Outside of cornering,
many riders, when pedalling hard (esp. while standing) will wag the
bike back and forth as they do so, introducing some side forces due to
the bike being leaned from side to side. It's difficult to stay up if
trying to pedal that hard in a fast, flat corner, though.

Even when such things are done, it still *shouldn't* deflect the wheel
enough to hit, but not everyone rides bikes as well-built and
fault-free as yours.

--
My email address is antispammed; pull WEEDS if replying via e-mail.
Typoes are not a bug, they're a feature.
Words processed in a facility that contains nuts.

 

[[email protected]]

Bugbear wrote:
> Once I straighten up, the rubbing stops.

You are certain it's the brakes? I ask because you said you couldn't
tell if it was front or rear, and I'd expect the first test you'd make
would be to pop the brake cables.

I once spent several days chasing a "rubbing brake pad" sound on my
commuter. It was a "sshh-sshh" sound in time with the wheels that only
occurred when cornering.

After eliminating and fenders as suspects and re-packing the rear hub
to no benefit, I discovered it was a recently-installed spoke-mounted
reflector causing the sound; despite the wheels being well-tensioned,
evidently something was happening during cornering that caused the
reflector to rub against spokes.

Just sayin' is all.

 

[Bugbear]

Well my bike is fairly new (about 4 months old), my LBS did a service
on it after the first month, and I've done about 2000km so far. I
sincerely hope that it's not the first signs of failing frame or forks,
or dodgy bearings! Considering the age of the bike, I would not be
expecting this to be the case. The bike cost AU$700 (flat bar road
bike) so it's an entry level bike. A flexy frame I suppose could be a
cause.

In the course of normal riding, I've also gone through one set of brake
pads (the original pads that came with the bike lasted for about
1500km).

This rubbing has not been chronic, and to be honest, it hasn't really
been a major problem. I was just curious as to the possible causes.

For now, I've given the brakes a bit more play (from an eyeball
measurement, about 1.5 to 2mm each side) and that seems to have fixed
things for now.

Thanks everyone for your suggestions.

 

[Johan Bornman]

On > But does it happen on both left and right turns?
> Is the inner brake cable closing the calipers because the housing isn't long
> enough to remain unbound when you turn?
>
> Gary Jacobson
> Rosendale, NY

Then taking a turn as the OP described, there is no noticeable "turn"
in the steering, eliminating that theory. Besides, even with steering
turn, it doesn't close the calipers. Try it on a stationery bike, with
the front wheel off and your fingers between the brake pads.

Johan Bornman

 

[[email protected]]

Tim McNamara writes:

>> Is this something I should be concerned about?

>> When I take corners at a not too outrageous speed, say a 90 degree
>> bend at about 30km/h (eg negotiating a typical street
>> intersection), I can hear my rims rubbing against the brake pads
>> (don't know if it's front or back). Once I straighten up, the
>> rubbing stops.

>> Is this a sign that I have set my brake pads too close to the rims?

> Back them off a bit and see what happens. There's no need to have
> your brake pads 1 mm from the rim, except in certain badly designed
> brake system such as V-brakes used with non V-brake (and indeed even
> with some V-brake) levers.

Better yet, how about manually pushing the wheel back and forth
between the brake pads and see how much slop there is in he wheel
bearings and how much force it takes.

Jobst Brandt

 

[Bill Westphal]

Tim McNamara <[email protected]> wrote:
> In article <[email protected]>,
> "Bugbear" <[email protected]> wrote:
>
>> Is this something I should be concerned about?
>>
>> When I take corners at a not too outrageous speed, say a 90 degree
>> bend at about 30km/h (eg negotiating a typical street intersection),
>> I can hear my rims rubbing against the brake pads (don't know if it's
>> front or back). Once I straighten up, the rubbing stops.
>>
>> Is this a sign that I have set my brake pads too close to the rims?
>
> Back them off a bit and see what happens. There's no need to have your
> brake pads 1 mm from the rim, except in certain badly designed brake
> system such as V-brakes used with non V-brake (and indeed even with some
> V-brake) levers.

You get much better leverage on the levers if you adjust the pads FAR
from the rims, so that you can pull the levers almost to touch the
bars. I pull my levers 1/2 way to the bars before the pads touch the
rims. I always did it to the other extreme, but someone enlightened
me a couple years back, and it took me awhile to get used to this, but
I think you're a lot safer that way. You've got a lot more stopping
power w/ one finger.

Bill Westphal

 

[[email protected]]

Bill Westphal writes:

>>> Is this something I should be concerned about?

>>> When I take corners at a not too outrageous speed, say a 90 degree
>>> bend at about 30km/h (eg negotiating a typical street intersection),
>>> I can hear my rims rubbing against the brake pads (don't know if it's
>>> front or back). Once I straighten up, the rubbing stops.

>>> Is this a sign that I have set my brake pads too close to the rims?

>> Back them off a bit and see what happens. There's no need to have your
>> brake pads 1 mm from the rim, except in certain badly designed brake
>> system such as V-brakes used with non V-brake (and indeed even with some
>> V-brake) levers.

> You get much better leverage on the levers if you adjust the pads FAR
> from the rims, so that you can pull the levers almost to touch the
> bars. I pull my levers 1/2 way to the bars before the pads touch the
> rims. I always did it to the other extreme, but someone enlightened
> me a couple years back, and it took me awhile to get used to this, but
> I think you're a lot safer that way. You've got a lot more stopping
> power w/ one finger.

You didn't say what size glove you wear but brake levers that I use
are made for people with average size hands and I find braking best
with up to 3mm clearance per brake pad. I think the choice of how
much clearance depends on hand size and bar type.

I use classic Cinelli bars with a circular arc bend both at the top
and the hook. The contoured hook was designed for people who found
the reach too far and this changed free lever position.

Jobst Brandt

 

[Bill Westphal]

[email protected] wrote:
> Bill Westphal writes:
>
>>>> Is this something I should be concerned about?
>
>>>> When I take corners at a not too outrageous speed, say a 90 degree
>>>> bend at about 30km/h (eg negotiating a typical street intersection),
>>>> I can hear my rims rubbing against the brake pads (don't know if it's
>>>> front or back). Once I straighten up, the rubbing stops.
>
>>>> Is this a sign that I have set my brake pads too close to the rims?
>
>>> Back them off a bit and see what happens. There's no need to have your
>>> brake pads 1 mm from the rim, except in certain badly designed brake
>>> system such as V-brakes used with non V-brake (and indeed even with some
>>> V-brake) levers.
>
>> You get much better leverage on the levers if you adjust the pads FAR
>> from the rims, so that you can pull the levers almost to touch the
>> bars. I pull my levers 1/2 way to the bars before the pads touch the
>> rims. I always did it to the other extreme, but someone enlightened
>> me a couple years back, and it took me awhile to get used to this, but
>> I think you're a lot safer that way. You've got a lot more stopping
>> power w/ one finger.
>
> You didn't say what size glove you wear but brake levers that I use
> are made for people with average size hands and I find braking best
> with up to 3mm clearance per brake pad. I think the choice of how
> much clearance depends on hand size and bar type.
>

THese days, the vulpineadaptive.com icebike mitts are so thick I sweat
> 10F, and I don't sweat much. So I just brake on the top in winter,
and go easy on descents. But normally very thin gloves. I'm actually
not sure why I wear gloves at all.

> I use classic Cinelli bars with a circular arc bend both at the top
> and the hook. The contoured hook was designed for people who found
> the reach too far and this changed free lever position.
>
> Jobst Brandt

I'm having trouble getting this whole vision exactly (and just
unsuccesfully searched for Cinelli's website, or other images of
classic Cinelli bars, and the hook shapes' effect on lever position),
but yes, I adjust for the particular eqmt, so whether I'm braking w/
one finger or two in the normal forward drop position the lever just
abut first unused finger at full braking force. The carbon bars I use
-- TTT Bio-Morphe, and now Calfee's barstem -- employ comfort, safety,
and well thought out and reasonable braking positions in ingenious and
subtle ways I only came to appreciate after putting lots of miles on.
Not to mention the exponential increase in comfort on bar top and near
and around the hoods, which allows me to shift weight slightly forward
when 5 hrs in the (leather) saddle is wearing on a new sore in the
making. I see Cinelli has a nice looking barstem, at close to $800
(!), but the FSA looks quite reasonable. The grams saved are almost
pointless, but the ergonomics posible with carbon fiber are amazing.

Bill Westphal

 

[[email protected]]

Bill Westphal writes:

>>>>> Is this something I should be concerned about?

>>>>> When I take corners at a not too outrageous speed, say a 90
>>>>> degree bend at about 30km/h (eg negotiating a typical street
>>>>> intersection), I can hear my rims rubbing against the brake pads
>>>>> (don't know if it's front or back). Once I straighten up, the
>>>>> rubbing stops.

>>>>> Is this a sign that I have set my brake pads too close to the
rims?

>>>> Back them off a bit and see what happens. There's no need to
>>>> have your brake pads 1 mm from the rim, except in certain badly
>>>> designed brake system such as V-brakes used with non V-brake (and
>>>> indeed even with some V-brake) levers.

>>> You get much better leverage on the levers if you adjust the pads
>>> FAR from the rims, so that you can pull the levers almost to touch
>>> the bars. I pull my levers 1/2 way to the bars before the pads
>>> touch the rims. I always did it to the other extreme, but someone
>>> enlightened me a couple years back, and it took me awhile to get
>>> used to this, but I think you're a lot safer that way. You've got
>>> a lot more stopping power w/ one finger.

>> You didn't say what size glove you wear but brake levers that I use
>> are made for people with average size hands and I find braking best
>> with up to 3mm clearance per brake pad. I think the choice of how
>> much clearance depends on hand size and bar type.

> These days, the vulpineadaptive.com icebike mitts are so thick I
> sweat 10F, and I don't sweat much. So I just brake on the top in
> winter, and go easy on descents. But normally very thin gloves.
> I'm actually not sure why I wear gloves at all.

No, not that reason. Glove size reveals how large you hands are. I'm
not interested in the gloves.

>> I use classic Cinelli bars with a circular arc bend both at the top
>> and the hook. The contoured hook was designed for people who found
>> the reach too far and this changed free lever position.

> I'm having trouble getting this whole vision exactly (and just
> unsuccessfully searched for Cinelli's website, or other images of
> classic Cinelli bars, and the hook shapes' effect on lever
> position), but yes, I adjust for the particular eqmt, so whether I'm
> braking w/ one finger or two in the normal forward drop position the
> lever just abut first unused finger at full braking force.

I only mentioned Cinelli to avoid explaining what brand they are
later. They are from the time that bars had circular arc bends
instead of lumpy anatomical kinks in the hooks (hooks being the loser
curve of drop bars).

> The carbon bars I use -- TTT Bio-Morphe, and now Calfee's barstem --
> employ comfort, safety, and well thought out and reasonable braking
> positions in ingenious and subtle ways I only came to appreciate
> after putting lots of miles on. Not to mention the exponential
> increase in comfort on bar top and near and around the hoods, which
> allows me to shift weight slightly forward when 5 hrs in the
> (leather) saddle is wearing on a new sore in the making. I see
> Cinelli has a nice looking barstem, at close to $800 (!), but the
> FSA looks quite reasonable. The grams saved are almost pointless,
> but the ergonomics possible with carbon fiber are amazing.

As I said, mine are old bars as in the pictures at:

http://www.sheldonbrown.com/brandt/

Jobst Brandt