Pros prefer sewups

Terry Morse <[email hidden]> wrote in news:tmorse-
[email hidden]:

Quoted message said:

Jobst Brandt said:

The faster you descend (above a creep) on alpine roads,
the harder you must brake and the hotter the rims

get

Quoted message said:

Quoted message said:

intermittently.

The worst case for rim heating is when you're descending
rather slowly, maybe 10 mph or so. The brakes absorb the
most energy on a given descent and the air cooling is the
lowest. I notice the most heating when descending dirt
roads of about 10-12%, since I can't

go

Quoted message said:

very fast and have to brake almost constantly.
--
terry morse Palo Alto, CA bike.terrymorse.combike.terrymorse.comOpen ↗

Broke my chainstay right at the dropout half a k from the
top of Ventoux last summer and had to come down entirely on
the front brake. At one point I stopped and touched the
front rim and burned my fingers to blisters.

Quoted message said:

Bill Lloyd said:

They pros aren't doing loaded touring with long, extended
heavy braking descents. Sure they use the brakes, but not
a lot -- the faster they go down the hills the better.

Don't repeat that old saw. The faster you descend (above
a creep) on alpine roads, the harder you must brake and
the hotter the rims get intermittently. This isn't a
hazard for clinchers but it is for tubulars on which the
glue melts and remains soft during the braking, thus
allowing the tire to creep until the valve breaks off or
the tire rolls.

That is the descending problem, RR is the other but
constant one.

Descents like that are the exception rather than the
rule. And if glue melting were a big problem, and I were
a Pro that had my tire choice, well I'd ride clinchers
for that day and tubies for the other days that don't
have similar descents.

I mean, look at this year's Giro. The first 16 days, there
have been 0 days with any real large descents. As such no
need for clinchers, yet.

Terry Morse said:

Quoted message said:

The faster you descend (above a creep) on alpine roads,
the harder you must brake and the hotter the rims get
intermittently.

Quoted message said:

The worst case for rim heating is when you're descending
rather slowly, maybe 10 mph or so. The brakes absorb the
most energy on a given descent and the air cooling is the
lowest. I notice the most heating when descending dirt
roads of about 10-12%, since I can't go very fast and have
to brake almost constantly.

That may be the worst case for heating air inside a clincher
tire but it is not the worst case for tubulars, where
instantaneous glue heating is the problem. In that case the
highest temperature achieved is as I described, when braking
to near stop for a hairpin turn after a straight steep run
at high speed. During that process, air cooling is
insignificant, while rim glue melts about as fast as the rim
gets hot, which is 1/2mv**2 watts of the rider and bicycle
kinetic energy.

Visualize the difference between slowly descending with the
brake on and standing the bicycle on its nose, so to speak,
from 40mph to a stop. The peak temperature does not have
much to do with history or air cooling at that moment.

Jobst Brandt [email hidden]

Mike Latondresse mikelat@no_spamshaw.ca said:

Terry Morse <[email hidden]> wrote in news:tmorse-
[email hidden]:

Quoted message said:

Jobst Brandt said:

The faster you descend (above a creep) on alpine roads,
the harder you must brake and the hotter the rims

get

Quoted message said:

Quoted message said:

intermittently.

The worst case for rim heating is when you're descending
rather slowly, maybe 10 mph or so. The brakes absorb the
most energy on a given descent and the air cooling is the
lowest. I notice the most heating when descending dirt
roads of about 10-12%, since I can't

go

Quoted message said:

very fast and have to brake almost constantly.
--
terry morse Palo Alto, CA bike.terrymorse.combike.terrymorse.comOpen ↗

Broke my chainstay right at the dropout half a k from the
top of Ventoux last summer and had to come down entirely
on the front brake. At one point I stopped and touched the
front rim and burned my fingers to blisters.

Well that was pretty stupid, wasn't it? Ever put your cat in
a microwave? That's also a bad idea, I hear.

dianne_1234 said:

Ted B usenet- said:

Jobst Brandt said:

A few years back, I noticed that most of the riders in
the Tour d'Suisse were on clinchers. I assumed these
same riders would probably ride the same in other
classics.

Wow, that's interesting observation, because if what you
say is true, then they've certainly switched back to
tubulars.

Having a look at photos from the past year, I see Lance
and USPS on Bontrager tubulars, CSC and Phonak on Zipp
tubulars, others (Cofidis, iBanesto, Once, Alessio, Fassa
Bartolo, etc.) riding Campy Bora and Hyperon tubulars,
and Ullrich on Lightweights...which are also tubulars.

Aha! Maybe the rise of the carbon rim is giving tubulars a
rebirth?

Yes... I had a pair of Lew wheels a few years back, they
were tubulars because that's what they required. I learned
the hard way that CF rims require different brake pads.

Quoted message said:

Any carbon clincher rims available?

Yes, Reynolds makes some. I saw the Lew prototypes. I have
some concerns about a bead that thin. Plus, if you run low
air at some point (and who doesn't?) and smack a pothole,
you could destroy your rim, where Al just tends to dent. No
thanks, on a $2000 wheelset :-P

Tim McNamara <[email hidden]> wrote in message news:<[email hidden]>...

Quoted message said:

(Qui si parla Campagnolo ) said:

Jobst-<< Of course this has all been battered around
here on wreck.bike for a long time. I've done the field
testing and have the data. The rest is supposition and
wishful thinking. >><BR><BR>

Sure has but the point was that most euro pros still use
tubies to race on. You implied that was nonsense, but
the truth is, most do.

Still waiting for someone to count tires and prove whether
this is correct or just a supposition. The only thing I've
been able to find thus far is reports from people who've
worked for them that the Mavic neutral support motos
provide clinchers exclusively, using Michelin and
Hutchinson.

Is Hutchinson still supplying tubular Carbon Comps to the
pros?

JP

Shayne Wissler said:

What chances does someone have at staying upright when
blowing out a tire at 30MPH? Does it blow out during the
deceleration, or sometime afterwards, once the air
inside the tire has absorbed more of the heat energy
from the rim?

Are we talking about clinchers or tubulars? Tubulars can
take the heat, its the glue that doesn't.

The tubular blowout is caused by ripping the stem out of the
tire and it doesn't occur unnoticed because before that
happens the tire piles up at the stem causing a perceptible
one-around lump. However, at that time, stopping isn't the
ideal remedy because it worsens creep.

Quoted message said:

Sometimes during a decent I'll stop at points and spray
water on my rims and wait for them to cool. Aside from the
temporary reduction in braking power from wet rims, is
this a bad idea?

That's fine for a tubular but why do you stop to do that? It
won't help a clincher much because it's the hot air in the
tire that is the problem and it doesn't change suddenly from
a short cooling of the rim. There it's the average
temperature that causes the problem.

Jobst Brandt [email hidden]

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

Quoted message said:

Shayne Wissler said:

What chances does someone have at staying upright when
blowing out a tire at 30MPH? Does it blow out during the
deceleration, or sometime afterwards, once the air
inside the tire has absorbed more of the heat energy
from the rim?

Are we talking about clinchers or tubulars? Tubulars can
take the heat, its the glue that doesn't.

Clinchers.

Quoted message said:

Quoted message said:

Sometimes during a decent I'll stop at points and spray
water on my rims and wait for them to cool. Aside from
the temporary reduction in braking power from wet rims,
is this a bad idea?

That's fine for a tubular but why do you stop to do that?
It won't help a clincher much because it's the hot air in
the tire that is the problem and it doesn't change
suddenly from a short cooling of the rim. There it's the
average temperature that causes the problem.

With the clinchers and a rim that's too hot to touch, I'm
worried about the temperature-induced high pressure blowing
the clincher off the rim or causing an inner tube failure.
Of course this is all based on a little knowledge and a lot
of ignorance; I don't know what range of parameters is
actually dangerous here, or what the likely consequences of
overheated rims are.

Shayne Wissler

Jobst Brandt said:

Terry Morse said:

The worst case for rim heating is when you're descending
rather slowly, maybe 10 mph or so. The brakes absorb the
most energy on a given descent and the air cooling is
the lowest. I notice the most heating when descending
dirt roads of about 10-12%, since I can't go very fast
and have to brake almost constantly.

That may be the worst case for heating air inside a
clincher tire but it is not the worst case for tubulars,
where instantaneous glue heating is the problem. In that
case the highest temperature achieved is as I described,
when braking to near stop for a hairpin turn after a
straight steep run at high speed. During that process, air
cooling is insignificant, while rim glue melts about as
fast as the rim gets hot, which is 1/2mv**2 watts of the
rider and bicycle kinetic energy.

Okay, I can see that situation, where there's a few thousand
watts goin into a rather small rim for a few seconds (except
the energy is
1/2mv**2 _joules_, not watts).

Plugging in a few reasonable numbers (5000 watts, 280 g rim)
produces a rim temperature rise of about 20 C/second.
Ignoring cooling, it would take less than 4 seconds to raise
the rim temperature to 100C, presumably well above the glue
melting temperature.
--
terry morse Palo Alto, CA bike.terrymorse.combike.terrymorse.comOpen ↗

Quoted message said:

You are missing something in that analysis: since you are
going slower, the heat has more time to dissipate.

I have a friend who overheated clinchers on relatively short
hills on a tandem. They rode some hills between a half mile
and a mile, but because they had their baby on the baby seat
they went down the hills at about 15mph. This was slow
enough to reduce the amount that air resistance absorbed the
energy and fast enough that the rim's heat did not disapate.

So I think you would have to go very slow, say under 5mph,
for the rim's heat to disapate faster then the brakes
create it.

Bruce

"David L. Johnson" <[email hidden]> wrote in
message "]news:[email hidden]...

Quoted message said:

Terry Morse said:

The worst case for rim heating is when you're descending
rather slowly, maybe 10 mph or so. The brakes absorb the
most energy on a given descent and the air cooling is
the lowest. I notice the most heating when descending
dirt roads of about 10-12%, since I can't go very fast
and have to brake almost constantly.

You are missing something in that analysis: since you are
going slower, the heat has more time to dissipate.

--

David L. Johnson

__o | Arguing with an engineer is like mud wrestling
with a pig...

You

Quoted message said:

_`\(,_ | soon find out the pig likes it! (_)/ (_) |

Quoted message said:

The tubular blowout is caused by ripping the stem out of
the tire and it doesn't occur unnoticed because before
that happens the tire piles up at the stem causing a
perceptible one-around lump. However, at that time,
stopping isn't the ideal remedy because it worsens creep.
Jobst Brandt

So the other question is, has glue changed over the past
25 years? or does using a mix ( such as combining tubie
glue with fastac ) or using fastac alone change the
melting temp of tubie glue or lessen the chances of
"creep" during hard braking?

Joe Yannie said:

Quoted message said:

The tubular blowout is caused by ripping the stem out of
the tire and it doesn't occur unnoticed because before
that happens the tire piles up at the stem causing a
perceptible one-around lump. However, at that time,
stopping isn't the ideal remedy because it worsens creep.

Quoted message said:

So the other question is, has glue changed over the past
25 years? or does using a mix (such as combining tubie
glue with fastac) or using fastac alone change the melting
temp of tubie glue or lessen the chances of "creep" during
hard braking?

No. The problem has always been the same for road racing
where tire change on the road had always been a requirement.
For this reason sticky (pressure sensitive) adhesives are
used. They are all temperature sensitive and are designed to
operate at "room" temperature and thereabouts. When they get
hot they melt, when it is freezing cold, tire changes are
difficult.

If you use hardening track glue (shellac) that is not
tacky once cured, you would be free of this problem. The
original reason for track adhesive was to reduce rolling
resistance, nothing else, because the tire cannot not
squirm on the rim with contact pressure from the road.
Hard glue coincidentally also solves heat problems but
then tires cannot be changed en route, besides being a
pain to apply and properly cure track glue that works only
on bare cloth base tapes. Road tires generally have a
rubber coated base tapes.

Just forget about tubulars. They are part of history, a bad
one at that. It was wheel myths and tubulars that inspired
me to write "the Bicycle Wheel" just to get rid of all the
mystery of why and how wheels work.

Jobst Brandt [email hidden]

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

Quoted message said:

Just forget about tubulars. They are part of history, a
bad one at that. It was wheel myths and tubulars that
inspired me to write "the Bicycle Wheel" just to get rid
of all the mystery of why and how wheels work.

Did I miss where you addressed the weight argument against
clinchers? Aren't tubulars significantly lighter?

Thinking about using tubulars vs. clinchers for my own
riding, the only reason I'd want to use a tubular would be
if I subscribed to the "no pain no gain" philosophy--it
sure would be a pain to use them. (that would be illogical
on two counts).

Shayne Wissler

Shayne Wissler said:

Did I miss where you addressed the weight argument against
clinchers? Aren't tubulars significantly lighter?

Depends on what you think is "significant", I guess. A
reasonable clincher tyre for every-day use is about 300
grams including the inner tube. A comparable tubular tyre
might be lighter than that, but not by much. The tubular rim
is also lighter, but the weight different is something like
20 grams per rim. Is that significant?

-as

Quoted message said:

No. The problem has always been the same for road racing
where tire change on the road had always been a
requirement. For this reason sticky (pressure sensitive)
adhesives are used. They are all temperature sensitive and
are designed to operate at "room" temperature and
thereabouts. When they get hot they melt, when it is
freezing cold, tire changes are difficult.

If you use hardening track glue (shellac) that is not
tacky once cured, you would be free of this problem. The
original reason for track adhesive was to reduce rolling
resistance, nothing else, because the tire cannot not
squirm on the rim with contact pressure from the road.
Hard glue coincidentally also solves heat problems but
then tires cannot be changed en route, besides being a
pain to apply and properly cure track glue that works only
on bare cloth base tapes. Road tires generally have a
rubber coated base tapes.

And pro racers generally have full mechanical support. When
was the last time you saw a pro fixing a flat or changing a
tire in the middle of a race? The support car comes to their
aid with a whole new wheel, and away they go. So for all we
know, their tires could be glued on permanently with 3M 5200
or something.

Quoted message said:

Just forget about tubulars. They are part of history, a
bad one at that. It was wheel myths and tubulars that
inspired me to write "the Bicycle Wheel" just to get rid
of all the mystery of why and how wheels work.

One man's mystery is another man's mystique...

Seriously, I wouldn't call it a bad part of history. Like
many other things, it was the best technology at some point,
but hung on about 30 years too long because of inertia in
business and consumer acceptance.

Personally, I'm glad to be rid of them.

Matt O.

"Antti Salonen" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

Shayne Wissler said:

Did I miss where you addressed the weight argument
against clinchers?

Aren't

Quoted message said:

Quoted message said:

tubulars significantly lighter?

Depends on what you think is "significant", I guess. A
reasonable clincher tyre for every-day use is about 300
grams including the inner tube. A comparable tubular tyre
might be lighter than that, but not by much. The tubular
rim is also lighter, but the weight different is something
like 20 grams per rim. Is that significant?

It's not significant to me. Maybe it is to racers, I
wouldn't know.

Shayne Wissler

Shayne Wissler said:

Quoted message said:

Just forget about tubulars. They are part of history, a
bad one at that. It was wheel myths and tubulars that
inspired me to write "the Bicycle Wheel" just to get rid
of all the mystery of why and how wheels work.

Quoted message said:

Did I miss where you addressed the weight argument against
clinchers? Aren't tubulars significantly lighter?

Quoted message said:

Thinking about using tubulars vs. clinchers for my own
riding, the only reason I'd want to use a tubular would be
if I subscribed to the "no pain no gain" philosophy--it
sure would be a pain to use them. (that would be illogical
on two counts).

They aren't called weight weenies for nothing. Weight
difference is truly insignificant. This is a couple of
ounces compared to 200 lbs of rider and bicycle, or 0.01%
for a four ounce difference. when you consider that this
times a 10% grade that you are climbing is 0.001% more drag.

Make sure you don't carry any water on your bicycle or on
your back because that weighs more than an entire tire.

Jobst Brandt [email hidden]

Matt O'Toole said:

Quoted message said:

No. The problem has always been the same for road racing
where tire change on the road had always been a
requirement. For this reason sticky (pressure sensitive)
adhesives are used. They are all temperature sensitive
and are designed to operate at "room" temperature and
thereabouts. When they get hot they melt, when it is
freezing cold, tire changes are difficult.

Quoted message said:

Quoted message said:

If you use hardening track glue (shellac) that is not
tacky once cured, you would be free of this problem. The
original reason for track adhesive was to reduce rolling
resistance, nothing else, because the tire cannot not
squirm on the rim with contact pressure from the road.
Hard glue coincidentally also solves heat problems but
then tires cannot be changed en route, besides being a
pain to apply and properly cure track glue that works
only on bare cloth base tapes. Road tires generally have
a rubber coated base tapes.

Quoted message said:

And pro racers generally have full mechanical support.
When was the last time you saw a pro fixing a flat or
changing a tire in the middle of a race? The support car
comes to their aid with a whole new wheel, and away they
go. So for all we know, their tires could be glued on
permanently with 3M 5200 or something.

That could be but they don' even know what the problem is so
they probably don't have a solution for it. I spent plenty
of time interviewing manufacturers and team mechanics and
found them to not understand the melting glue phenomenon or
the RR problem. You may recall that the RR tests were the
first definitive indicators of how bad the road glue problem
was and why there is road and track glue.

Besides that, you cannot hard glue a rubberized base tape
and most road tubulars have rubberized base tapes.

Quoted message said:

Quoted message said:

Just forget about tubulars. They are part of history, a
bad one at that. It was wheel myths and tubulars that
inspired me to write "the Bicycle Wheel" just to get rid
of all the mystery of why and how wheels work.

Quoted message said:

One man's mystery is another man's mystique...

Religion. Don't mess with mine!

Quoted message said:

Seriously, I wouldn't call it a bad part of history. Like
many other things, it was the best technology at some
point, but hung on about 30 years too long because of
inertia in business and consumer acceptance.

Somehow a lot of that got lost during WWII because I found
no one who could tell me what the purpose of track and road
glue for tubulars was. No one knew what spoke stress
relieving was except that some wheel builders had odd things
they did because it "made wheels last longer." They had no
idea what that step did. I saw it in Italy when a 5' 2"
mechanic walked around with tennis shoes on the spokes of a
wheel laid on the floor.

Quoted message said:

Personally, I'm glad to be rid of them.

Amen. Or was that another more appropriate word? I believe.

Jobst Brandt [email hidden]

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

Quoted message said:

.. Just forget about tubulars. They are part of history, a
bad one at that. It was wheel myths and tubulars that
inspired me to write "the Bicycle Wheel" just to get rid
of all the mystery of why and how wheels work.

Jobst, as a "solution provider", why don't you suggest or
contact chemical companies to up with a higher T glue?
Afterall, we have dope that can push a human to run under
9.XX sec and other as yet traceable performance enhancing
compounds that are "developed". I know its all about
economics but many people still like tubies.

[email hidden] wrote:

<snip>

Quoted message said:

They aren't called weight weenies for nothing. Weight
difference is truly insignificant. This is a couple of
ounces compared to 200 lbs of rider and bicycle, or
0.01% for a four ounce difference. when you consider
that this times a 10% grade that you are climbing is
0.001% more drag.

Make sure you don't carry any water on your bicycle or on
your back because that weighs more than an entire tire.

Jobst Brandt [email hidden]

Four ounces out of 200 lb is 0.125%, not 0.01%. Climbing a
10% grade, most of the effort goes into overcoming gravity,
not 10% of it, so it takes almost 0.125% more energy, not
0.001% more. That's still only about 4 sec. difference on an
hour-long hillclimb.

Of course water is heavy, and people racing uphill carry as
little of it as they can. I'll predict there won't be a lot
of 100-oz Camelbaks on the Alpe d'Huez TT.

I stopped using sewups about 20 years ago; for me they
aren't worth the expense and the bother, but it seems most
pros still use them most of the time.

Dave Lehnen