rim temps

Callistus Valerius said:

Was going down some 8% with switchbacks, and I was braking a lot of the way.
Stopped on the side of the road and felt the rims. The rim on the back was
red hot, but the one on the from was just slightly warm. I was using equal
pressure on on both brakes. Why would the rim temps differ so much?

Dear Cal,

The rims are saying that the friction was not the same as
far as the brake pads and rims were concerned, assuming
roughly equal pads and rims.

If things like brake pads and rims really are the same fore
and aft, you may have been mistaken about applying equal
pressure on both brakes.

(With most people, the dominant hand is usually noticeably
stronger, while the other hand is often more sensitive and
nimble, so applying equal pressure is harder than we think.)

If the pressure really was equal, then your rear brake pads
are probably in much better shape than your front pads, a
common situation, and provided much more friction for the
same pressure.

Or you could be toying with us and using a front disc brake.

Carl Fogel

Quoted message said:

(With most people, the dominant hand is usually noticeably
stronger, while the other hand is often more sensitive and
nimble, so applying equal pressure is harder than we think.)

I might be the exception, but I thought people with the stronger brake have
more control with that hand.

I ride right-front and left-rear (as all bicycles should be) and ride
street/urban stuff so my skill is probably significantly higher than the
average cyclist, but do you think people are ham-fisted with their dominant
hand, while the other hand would be more nimble? I would think that the
dominant hand would be more sensitive, as it would be used more often.

--
Phil, Squid-in-Training

Quoted message said:

Quoted message said:

Was going down some 8% with switchbacks, and I was braking a lot of the

way.

Quoted message said:

Quoted message said:

Stopped on the side of the road and felt the rims. The rim on the back

was

Quoted message said:

Quoted message said:

red hot, but the one on the from was just slightly warm. I was using

equal

Quoted message said:

Quoted message said:

pressure on on both brakes. Why would the rim temps differ so much?

Dear Cal,

The rims are saying that the friction was not the same as
far as the brake pads and rims were concerned, assuming
roughly equal pads and rims.

If things like brake pads and rims really are the same fore
and aft, you may have been mistaken about applying equal
pressure on both brakes.

(With most people, the dominant hand is usually noticeably
stronger, while the other hand is often more sensitive and
nimble, so applying equal pressure is harder than we think.)

If the pressure really was equal, then your rear brake pads
are probably in much better shape than your front pads, a
common situation, and provided much more friction for the
same pressure.

Or you could be toying with us and using a front disc brake.

Carl Fogel

no equal pads, brakes, etc. It could be I'm not using equal pressure in
reality, but it feels like it in the hands. I was thinking, maybe the front
rim gets more cooling, but it wouldn't seem to be that different.

ZeeExSixAre said:

Quoted message said:

(With most people, the dominant hand is usually noticeably
stronger, while the other hand is often more sensitive and
nimble, so applying equal pressure is harder than we think.)

I might be the exception, but I thought people with the stronger brake have
more control with that hand.

I ride right-front and left-rear (as all bicycles should be) and ride
street/urban stuff so my skill is probably significantly higher than the
average cyclist, but do you think people are ham-fisted with their dominant
hand, while the other hand would be more nimble? I would think that the
dominant hand would be more sensitive, as it would be used more often.

"Used more often" for what?

This isn't relevant -- it's relatively easy to train this. As a
counter example, "normal" people can't brake a car AT ALL with their
left foot... there's no "training" there so when they hit the brakes,
they'll hit them too hard and it will be VERY jerky.

However, many rally and race car drivers brake almost EXCLUSIVELY with
their left foot, with an extremely fine degree of control. It just
takes practice. I probably get 700 hours a year on the bike -- I think
that's enough practice to have plenty of "control" with my left hand.

ZeeExSixAre said:

Quoted message said:

(With most people, the dominant hand is usually noticeably
stronger, while the other hand is often more sensitive and
nimble, so applying equal pressure is harder than we think.)

I might be the exception, but I thought people with the stronger brake have
more control with that hand.

I ride right-front and left-rear (as all bicycles should be) and ride
street/urban stuff so my skill is probably significantly higher than the
average cyclist, but do you think people are ham-fisted with their dominant
hand, while the other hand would be more nimble? I would think that the
dominant hand would be more sensitive, as it would be used more often.

Dear Phil,

Use helps, but typically, the dominant hand is stronger, but
less sensitive and nimble. There are all sorts of odd little
habits that illustrate this.

If you're right-handed, interlace your fingers--it's likely
that your left thumb ends up on top. For the same reasons,
you'll probably shuffle cards with the last card of the
left-hand stack ending up on top and then flip and deal the
cards with your left hand.

If you're right-handed, it's likely that you can use your
left hand alone to smooth and pat your hair into place when
you have no comb and part it on the left--using your right
hand alone would feel quite awkward. (This behavior persists
even when no hair is left to groom.)

If you're right-handed, it's likely that you hold books in
your right hand and take care of turning and riffling pages
forwards or backwards with your left hand. You'll also
probably thumb through pages and currency with your left
thumb.

If you're right-handed, it's likely that you will tie knots
like a double half-hitch around a rail by holding the line
taut with your right hand and threading the end with your
left.

The most delicate fingering in music occurs on unfretted
strings--all the fingers are used, all must press down with
astonishing but unguided accuracy. Since most people are
right-handed, violins are fingered with the left hand.

Most people can think of two apparent exceptions, namely
handwriting and the modern use of a computer mouse. Both
actions, however, turn out to involve far less finger
nimbleness and sensitivity than we think.

Handwriting actually makes surprisingly little use of finger
dexterity. The pen is gripped with the thumb and a finger or
two and it is the whole hand and even forearm that does most
of the moving. (Stick your index finger up in the air and
"write" your name with it to see how little finger motion is
really involved.)

The same is true of the computer mouse. Even more than the
pen, the mouse is moved by the whole hand and forearm. Take
a moment and see how well you can move the mouse around the
screen with it gripped using your whole hand (normal),
between your thumb and forefinger (lazy), between your
thumb and just your little finger (silly), and between your
first and second fingers (absurd). You can probably move the
pointer quite quickly and accurately. (Try tying a knot with
just your thumb and little finger or with just your first
and second fingers and the difference in dexterity required
will become obvious.)

Now try using the mouse in these odd ways with your other
hand--you may be surprised at how good you are at moving the
pointer around with the wrong hand.

But switch to a track-ball or touch-pad, where actual finger
dexterity becomes important, and you'll find it much harder
to move the pointer around the screen.

As for sensitivity, perhaps the best example is surgery.
When a right-handed surgeon is groping about blindly in your
innards, trying to feel for tiny holes or lumps, he does it
with his left gloved hand if at all possible.

Dominant eye and the need for strength, along with practice
and habit, account for all sorts of odd left-right
situations.

The reins, for example, are typically held in the left hand,
even though the left hand is usually weaker, not for
delicacy of control but because the stronger right hand
needs to be free to use a long-forgotten sword.

The bow is usually held out with the typically weaker left
hand so that the stronger right hand can actually draw the
arrow back and so that the normally dominant right eye can
be used for sighting--which explains how rifles came to be
held.

The British drive on the left, but that is probably due to
the sort of accident that causes the eye to migrate to the
wrong side of the nose in some species of flounders, an
embarrassing genetic disaster that no decent person would
mention.

Even-handedly,

Carl Fogel

Carl, I'm an odd one (I'm right-handed):

Quoted message said:

If you're right-handed, interlace your fingers--it's likely
that your left thumb ends up on top. For the same reasons,
you'll probably shuffle cards with the last card of the
left-hand stack ending up on top and then flip and deal the
cards with your left hand.

Nope - right thumb over left and I deal with the right.

Quoted message said:

If you're right-handed, it's likely that you can use your
left hand alone to smooth and pat your hair into place when
you have no comb and part it on the left--using your right
hand alone would feel quite awkward. (This behavior persists
even when no hair is left to groom.)

I use my right with a comb for everything.

Quoted message said:

If you're right-handed, it's likely that you hold books in
your right hand and take care of turning and riffling pages
forwards or backwards with your left hand. You'll also
probably thumb through pages and currency with your left
thumb.

Nope - hold book with left and turn pages with right... currency with right
also.

Quoted message said:

If you're right-handed, it's likely that you will tie knots
like a double half-hitch around a rail by holding the line
taut with your right hand and threading the end with your
left.

Dunno... I don't tie knots 😉

Quoted message said:

The most delicate fingering in music occurs on unfretted
strings--all the fingers are used, all must press down with
astonishing but unguided accuracy. Since most people are
right-handed, violins are fingered with the left hand.

This is true.

Quoted message said:

But switch to a track-ball or touch-pad, where actual finger
dexterity becomes important, and you'll find it much harder
to move the pointer around the screen.

I use a Logitech trackball with my 2nd, 3rd, and 4th fingers. I am awkward
with mice but perform very well in computer games with the trackball because
I don't use gross arm/hand movements.

Quoted message said:

As for sensitivity, perhaps the best example is surgery.

These other examples are interesting, too.

As for my oddness, I ride with my left being my power foot, but I bunnyhop
and do all my other tricks with my right foot forward. Almost everyone else
uses the same foot for both.

As for trials, I use my power foot to get up into the backhop, but I need to
use my right foot to power forward for forward hops.

--
Phil, Squid-in-Training

ZeeExSixAre said:

Carl, I'm an odd one (I'm right-handed):

Quoted message said:

If you're right-handed, interlace your fingers--it's likely
that your left thumb ends up on top. For the same reasons,
you'll probably shuffle cards with the last card of the
left-hand stack ending up on top and then flip and deal the
cards with your left hand.

Nope - right thumb over left and I deal with the right.

Quoted message said:

If you're right-handed, it's likely that you can use your
left hand alone to smooth and pat your hair into place when
you have no comb and part it on the left--using your right
hand alone would feel quite awkward. (This behavior persists
even when no hair is left to groom.)

I use my right with a comb for everything.

Quoted message said:

If you're right-handed, it's likely that you hold books in
your right hand and take care of turning and riffling pages
forwards or backwards with your left hand. You'll also
probably thumb through pages and currency with your left
thumb.

Nope - hold book with left and turn pages with right... currency with right
also.

Quoted message said:

If you're right-handed, it's likely that you will tie knots
like a double half-hitch around a rail by holding the line
taut with your right hand and threading the end with your
left.

Dunno... I don't tie knots 😉

Quoted message said:

The most delicate fingering in music occurs on unfretted
strings--all the fingers are used, all must press down with
astonishing but unguided accuracy. Since most people are
right-handed, violins are fingered with the left hand.

This is true.

Quoted message said:

But switch to a track-ball or touch-pad, where actual finger
dexterity becomes important, and you'll find it much harder
to move the pointer around the screen.

I use a Logitech trackball with my 2nd, 3rd, and 4th fingers. I am awkward
with mice but perform very well in computer games with the trackball because
I don't use gross arm/hand movements.

Quoted message said:

As for sensitivity, perhaps the best example is surgery.

These other examples are interesting, too.

As for my oddness, I ride with my left being my power foot, but I bunnyhop
and do all my other tricks with my right foot forward. Almost everyone else
uses the same foot for both.

As for trials, I use my power foot to get up into the backhop, but I need to
use my right foot to power forward for forward hops.

Dear Phil,

As you say, you may be an odd one.

Left-handedness is not quite as rare as we think, since many
left-handed people people are trained to become
right-handed. In baseball, you might end up as throws right,
bats left.

And people do have varying degrees of ambi-dextrous skill.
Watch a major-league warm-up session closely, and you'll
find an irritating number of players who can pitch batting
practice with either arm.

Lock-picking provides the illustration of the lack of
ambi-dextrous skill. Most people are right-handed and use
their right hand for the pick and their left hand for the
tension wrench (the reasons are tricky). Faced with a lock
on the left side of a door almost flush with a wall, even
professional locksmiths can become quite frustrated, just
like a violin player asked to use the wrong hand. I once saw
locksmith deal with such a door by turning his back to it,
bending over, and pretty much picking it upside-down. It was
horribly awkward, but still better than trying to use the
wrong, untrained hand to work on the lock.

Carl Fogel

Callistus Valerius said:

Quoted message said:

Quoted message said:

Was going down some 8% with switchbacks, and I was braking a lot of the

way.

Quoted message said:

Quoted message said:

Stopped on the side of the road and felt the rims. The rim on the back

was

Quoted message said:

Quoted message said:

red hot, but the one on the from was just slightly warm. I was using

equal

Quoted message said:

Quoted message said:

pressure on on both brakes. Why would the rim temps differ so much?

Dear Cal,

The rims are saying that the friction was not the same as
far as the brake pads and rims were concerned, assuming
roughly equal pads and rims.

If things like brake pads and rims really are the same fore
and aft, you may have been mistaken about applying equal
pressure on both brakes.

(With most people, the dominant hand is usually noticeably
stronger, while the other hand is often more sensitive and
nimble, so applying equal pressure is harder than we think.)

If the pressure really was equal, then your rear brake pads
are probably in much better shape than your front pads, a
common situation, and provided much more friction for the
same pressure.

Or you could be toying with us and using a front disc brake.

Carl Fogel

no equal pads, brakes, etc. It could be I'm not using equal pressure in
reality, but it feels like it in the hands. I was thinking, maybe the front
rim gets more cooling, but it wouldn't seem to be that different.

Dear Cal,

I agree that the difference in air-flow over a normal front
and rear tire doesn't seem likely to account for the kind of
temperature difference that you noticed.

Our ability to feel different effort with different hands is
not usually as good as we'd think.

You can test this with a typical bathroom scale, squeezing
with one hand and then the other while someone else writes
down the results--most people will find their dominant hand
producing higher readings even when they think that they're
squeezing the same amount.

Another demonstration that's closer to bicycle brake
squeezing is to take one of those hand-grip exercise springs
and start doing two dozen rapid squeezes with one hand and
then repeating with the other. People generally find that
one hand tires noticeably faster than the other.

Another possible explanation is that although the pads and
rims were identical when first installed, the surfaces have
worn differently, possibly even during the ride itself. In
normal riding, rear pads last much longer because most
braking is done with the front. You might have been
descending with well-worn front pads and rear pads in
almost-new condition.

But identical pads, rims, and pressures should produce
roughly similar friction and heat.

Of course, you might have not realized that you were using
the rear brake alone at a low speed where you might not
think that it mattered. Jobst Brandt has mentioned blowing a
rear tire off in such a situation:

"My friend stopped to take pictures so I waited for him
riding the rear brake over the lever hood at less than 10mph
when BAM! the tire that I had previously ridden over steep
curving descents blew off."

http://groups.google.com/groups?q=g:thl905373870d&dq=&hl=en&lr=&ie=UTF-8&selm=amQoc.11091%24Fo4.145606%40typhoon.sonic.net

I think (but may be wrong) that Jobst was saying that he was
going slowly with rear-wheel-only braking down a steep grade
with very little wind cooling and BAM! went the tire on his
overheated rear rim:

"As I said, it was the rear tire and I merely braked with
one hand over the lever hood keeping the bicycle at just
over walking speed as I waited or my friend. It never
occurred to me that this would blow off the tire, having
descended this road many times without incident
with many others."

http://groups.google.com/groups?q=g:thl2648978382d&dq=&hl=en&lr=&ie=UTF-8&selm=m7Yoc.11159%24Fo4.146300%40typhoon.sonic.net

Like you, Jobst was surprised by how hot his rear rim had
gotten with what he had considered far from exciting
braking. If nothing else, your hot rear rim is in good
company.

Carl Fogel

Quoted message said:

Was going down some 8% with switchbacks, and I was braking a lot of the way.
Stopped on the side of the road and felt the rims. The rim on the back was
red hot,

now that's something I would like to see. was the tire flaming? aluminum tends
to melt before it gets red hot (G)

--
Knight-Toolworks & Custom Planes
Custom made wooden planes at reasonable prices
See http://www.knight-toolworks.com For prices and ordering instructions.

"Bill Lloyd" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

On 2004-07-22 21:12:15 -0700, "ZeeExSixAre"

"Used more often" for what?

This isn't relevant -- it's relatively easy to train this. As a
counter example, "normal" people can't brake a car AT ALL with their
left foot... there's no "training" there so when they hit the brakes,
they'll hit them too hard and it will be VERY jerky.

However, many rally and race car drivers brake almost EXCLUSIVELY with
their left foot, with an extremely fine degree of control. It just
takes practice. I probably get 700 hours a year on the bike -- I think
that's enough practice to have plenty of "control" with my left hand.

Coming from a place (Australia) where the front brake is always on the right
I just can't understand how one could choose to ride a bicycle set up
opposite to every motorbike (ever?) made. Riding pedal and motor powered
units about equally, I must admit that in a panic stop I find I've pulled
the clutch lever......oh well.....
Hugh Fenton

On Sat, 24 Jul 2004 16:25:32 +0200, "Hugh Fenton" <[email hidden]>

Quoted message said:

Coming from a place (Australia) where the front brake is always on the right
I just can't understand how one could choose to ride a bicycle set up
opposite to every motorbike (ever?) made.

I don't ride motorcycles and probably never will. That's why.

JT

Callistus Valerius said:

Was going down some 8% with switchbacks, and I was braking a lot of the way.
Stopped on the side of the road and felt the rims. The rim on the back was
red hot, but the one on the from was just slightly warm. I was using equal
pressure on on both brakes. Why would the rim temps differ so much?

Possible explanations, in no particular order...

One cable may move more freely than the other, producing unequal
application despite equal lever effort.

The calibration of the tension sensors in your hands may be a bit off;
check the calibration and rerun the descent.

The pads on front and rear may have different surface characteristics
even if they're the same material, and this can have an effect on the
amount of friction produced.

The airflow over the front wheel is less obstructed, and may have
cooled it better.

You checked the rear wheel first, and burned out enough neurons in the
temp sensors that the front wheel (and possibly all subsequent) will
seem cooler than they really are.

The black helicopters were aiming a high-intensity radar unit at your
rear wheel during the last part of the descent, and the microwaves
heated it.

Something else that none of us know about was going on...

--
Typoes are a feature, not a bug.
Some gardening required to reply via email.
Words processed in a facility that contains nuts.

When you store your bike at home, do you hang it from the rear wheel
only?

- -

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

Chris Zacho ~ "Your Friendly Neighborhood Wheelman"

Chris'Z Corner
http://www.geocities.com/czcorner