How Much Glue?

Nuck 'n Futz said:

[email hidden] wrote:

[unimportant stuff snipped}

Quoted message said:

What an ass. Proposing a hypothesis for discussion is not the same as
claiming something to be true

So you're in William Bennett's corner then? Good, he needs the support!

I'm not sure I follow you, but you seem to be saying that when Bennett
said that you could cut the crime rate by aborting all African American
babies he was only throwing it out for discussion, not saying we should
absolutely do it.

If that's what you're saying, then, no, I'm not in William Bennett's
corner either way.

Whatever his excuse is, Bennett's comment was extraordinarily
insensitive and leaves me wondering what kind of person would have such
an idiotic thing pop into his head, let alone actually voice it over
the air.

On Thu, 06 Oct 2005 17:00:44 GMT, [email hidden]

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Vittoria Mastik One was not around then, from what I can tell.

It has been around as long as Vittoria has been in the tubular business.

Really?

Was it sold under a different name. I never saw it in the major mail
order catalogs or the bike shops near where I live more than perhaps
10 years ago.

JT

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So, again, [censored].

I see you can't control your emotions. Try to be civil if you want
your utterances to be taken seriously.

Jobst, you are rewarding his rudeness with a relatively polite reply.
Worse, you are engaging him in the discussion without any sort of
commitment (from him) to civility. If you don't mind, then fine, but if
you keep rewarding him, you can expect more of the same.

Tom

Tom Reingold said:

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So, again, [censored].

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Quoted message said:

I see you can't control your emotions. Try to be civil if you want
your utterances to be taken seriously.

Quoted message said:

Jobst, you are rewarding his rudeness with a relatively polite
reply. Worse, you are engaging him in the discussion without any
sort of commitment (from him) to civility. If you don't mind, then
fine, but if you keep rewarding him, you can expect more of the
same.

I don't write this stuff to please myself but rather to let readers
know there is another explanation for what I generally call myth and
lore, the stuff without merit that is passed from one generation of
bicyclists to the next. The rude responses do two things, they
generally invoke the myth that needs airing, and they do it in a way
that civilized readers recognize as rude and uninformed of the matter
at hand.

As I said above, the readers that count can tell the difference.
There is only one kind of appropriate reply, regardless of what tone
the critic uses, and that is a civil and polite one. Stooping to use
a similarly rude response is not constructive.

When a subject comes up often enough, I often write a short essay on
it and put it in the FAQ so I don't need to write an explanation.
Sheldon was kind enough to offer a bit of space for that on his web
site:

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

Jobst Brandt

Quoted message said:

You make obvious that you do not understand how tires support loads.
Has it occurred to you that automotive tire shops mount tires on
wheels, inflate them and subsequently put them in place to support the
car. You cannot see the difference in pressure on a tire pressure
gauge. That is why you can inflate your spare in a car to 30psi to be
subsequently used at 30psi when you let the car off the jack.

Quoted message said:

From http://www.sheldonbrown.com/brandt/rim-support.html :

" it takes several strokes of a frame pump to increase the pressure of
a tire from 100 psi to 101"

It takes a very small deflection to raise the pressure in a tubular by
5psi with a floor pump. Yes, a full stroke to pressurize the air to the
level that is already in the tire, but a much smaller amount to raise
it above what it already is. Has anyone actually tried to measure the
volume reduction and corresponding change in pressure of a tire when it
is pushed to the rim?

Let's consider a different question: do you believe that clinchers are
more susceptible to pinch flats than tubulars, yes or no? Why?

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Part of the tube, the bead and part of the sidewall?

Yes, and what effect does that have on the parameter you claim are
different between clinchers and tubulars?

I merely answered a question you asked, "What parts of a clincher are
not visible?" I did not claim anything.

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I think I do.

Please demonstrate that rather than dodging with quips.

[censored], yet again. I had physics and trig.

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It's a stupid argument, regardless, because it's a false
dichotomy: you are probably one of only a handfull of people in the
world that have an opinion on it that would claim
that tubulars and clinchers are equally subject to pinch flats.

That arises today because most of the tubular riders don't ride
unpaved roads and never get to cobbled streets.

So, tubular riders have to ride cobblestones to get pinch flats;
clincher riders get them anywhere if they don't pump their tires up to
120psi.

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So, again, [censored].

I see you can't control your emotions. Try to be civil if you want
your utterances to be taken seriously.

No, you don't "see". I'm just responding to the rude, nasty, belittling
manner of your argument that has been repeated over and over again in
responding to me and just about everyone else on this ng. I just take
it out in the open, that's all.

But I'm surprised no one's ever knocked your teeth out. A lot of people
wouldn't tolerate your behavior toward them in person without losing
their temper.

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Which has nothing to do at all with the tall tale about you coining the
phrase.

You seem to have problems with that.

No, not at all, I enjoy a fairy tale.

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They measure it indirectly by doing coast-down testing.

As I pointed out, that doesn't give the same information direct drag
measurements as a range of inflation pressures do. There is no way
you can see what effect inflation pressure has on RR unless it is
measured over a range of pressures.

However, they are completely adequate to dispute the conclusion that
clinchers are inherently superior to tubulars.

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If the tubulars are not unknown, then you should be able to tell us
here the make and model. If you do, I would rephrase my statement
thusly: "that with some unknown but admittedly inferior glue and
gluing technique (you implied that the gluing technique allowed for
easy removal to replace a tire after a flat; and you definitely did
not use the best glue available today), some Avocet clincher
demonstrated lower rr than a (fill in tubular name) tubular that has
been out of production for (fill in number of years out of
production) years and whose performance was not quantified by
comparison to other tubulars, and that that advantage disappeared
with the better bond provided by track shellac."

I take it you haven't looked at the data because the tires are all
identified on the graph:

I take it you didn't read the part where I said your link you
previously posted didn't work. But, okay, like I said, consider my
earlier statement modified.

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http://skyscrapercity.com/showthread.php?t=252897

This brings up an interesting thread on the Spanish AVE high-speed
trains.

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In light of this, I don't understand what your are writing about, not
having looked at the graphs that show the tubular offset due to rim
losses. The curves clearly show a family of similar curves in which
tubulars have the best characteristics (slope of curve and flatness)
but are out of place by a constant. These curves are closely related
most of them being identical except for a bas multiplier.

I have no doubt that your experiment did reveal a squirm caused by the
glue. My problem is that you leap from there to the grand conclusion
that it must be present on all road tires with all glues under all
circumstances.

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You ought to be able to give an answer to that when you have been
arguing that case all along by saying that the test values are
irrelevant because they were made by older tires.

No, I said older glues. _You_ said older tires. It was not until you
brought it up that I even discussed whether the tires might be
obsolete. I don't know whether there is anything that could be done or
has been done to improve the rr qualities of tubular tires.

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Do you not believe that tubulars move on tacky road glue

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I don't know whether a tire glued on properly with it would "move"
significantly more than shellac. And neither do you, because you
didn't test it.

You seem to base your disagreement on the use of Vittoria Glue.

No, I base it on the fact that you did _not_ use Vittoria glue, and
that you did not document your gluing process or manipulate it as a
variable.

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Is
that the only thing you think is germane in this discussion. Is it
that the whole subject depends on whether or not the tests were done
with this glue?

I already enumerated what I considered to be flaws in the design of
your experiment relative to your sweeping conclusions.

Quoted message said:

You'll notice that other adhesives are used by the
tubular users in this forum. Do you think they have no reasons for
doing so?

Myth and Lore? I think that after you read the test data there is no
good reason to use any other glue, except perhaps availability. The
test data is significant enough to make me seek it out.

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Sure. And _maybe_ by using the best glues on the road.

So if this is not a problem with tubulars, how do you justify the
search for the ideal glue, one that is almost inseparable from the
tire and rim yet one that allows changing a tire. This indicates to
me that there is a problem with gluing them to rims that is worth
addressing.

It is definitely an issue. If you use tubulars that are as well glued
as is allowed by Mastik One, you will have to rethink the way you get
the tire off. It is not really any more difficult, just different.

Quoted message said:

This sounds arduous. You may recall that quick and easy tire changes
is one of the main advantages touted for tubulars.

It's actually not, and I don't find it that much slower, maybe a few
seconds with practice.

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Yes, but the difference may not be significant, and unless the
shellac was used with perfect technique (whatever that is) there is
always the possibility that approaching perfect technique with a
soft glue could give better results that you got with the shellac.

"MAY NOT". I think you'll have to give more evidence than that. I
showed you my data, you show me yours.

No, you didn't show me data for this, and that's my point: you use
other data and claim it is this. I am questioning your conclusions, not
claiming that I have proof otherwise.

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So it wasn't Avocet, who had a major stake in getting clinchers into
the "serious" cycling market? Regardless, it is obvious that they were
dependent on tubular myth and lore as opposed to experimentation in
their glue and their gluing technique.

These tests were performed in Japan by IRC at the time they sponsored
racing and served racing teams.

I think we all know what their stake was.

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On the contrary, I am saying that your research suggests that the
best way to mount a tire is to minimize the thickness of the glue
layer while insuring a strong, secure bond.

Yes, go on, and what does that have to do with the rolling resistance
cause by the interface between tire and rim. As I pointed out, rims
show base tape pattern in the aluminum from this motion. That means
that upon heating from braking, the glue migrates out of the highest
pressure contact and allows the fabric of the tire to contact the
metal. Is that thin enough?

Use a better glue with better heat resistance. Do you want me to tell
you again what that would be?

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As I said, regardless of who mounted the tire and with which rim
glue, base tapes wore out and rims showed friction wear in the
aluminum.

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That does not mean that anyone used the best glue or the best
technique.

You are retreating.

Hardly.

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The contention is that tubulars mounted on
pressure sensitive (tacky) glue have losses. Now you are saying that
users are not using your preferred adhesive so the concept is flawed.

Partly, but what I am saying is that unless you can show that you used
the best glue with the best technique your sweeping condemnation of
tubulars is not justified.

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I take that as your interpretation of technical explanations of
natural phenomena that disagree with your beliefs.

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No, take it as general relativity changed the understanding of
gravity that Galileo and Newton gave us.

In an interview with one of Einstein's colleagues the old professor
said with irritation "He had no right in publishing his relativity
papers because he didn't do the research." This is not an original
tactic as you can see.

Well, I definitely didn't do the research, either.

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Attack the messenger, not the message.

No, it's the message alright: your sweeping condemnation of tubulars
tires based on a very limited set of data using obsolete materials.

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I think you'll find that a 25mm clincher has the same deflection to
bottoming as a 25mm tubular, the only difference are a few 0.001" of
casing thickness and tube thickness difference but then clinchers with
thin latex tube and the same TPI are around and they are
indistinguishable in displacement from tubulars. In fact, it takes a
careful eye to see whether a tire is a tubular or clincher unless
there is rim glue smeared around.

I think you missed what supports a rim off the ground but that can be
corrected at:

http://www.sheldonbrown.com/brandt/rim-support.html

"unit casing tension is equivalent to inflation pressure times the
radius of curvature divided by pi. As the curvature reduces when the
tire bulges out, the casing tension decreases correspondingly. The
inflated tire supports the rim primarily by these two effects."

The casing tension is decreased as the tire bulges out in response to
an external force. The local loss of tension creates a localized
difference in casing tension between that part of the tire and the rest
of it, and the pressure acts on the tire as the outside force is
dissapated to equalize the tension. So the effect of the pressure is
not dependent on some increased pressurization caused be compression of
the tire, but by the difference between atmospheric pressure and the
pressure inside the tire (which is obviously a much larger difference)
acting to restore tension to some state of equilibrium for the tire as
a whole.

Nevertheless, the compressibility of an inflated tire is dependent on
its volume, and two tires of equal "radius" above the rim edge,
pressurized to the same degree, will not be equally compressible if the
volume of one tire is different from the other. It looks to me like the
formula above may be flawed in its use of pi; this would be a
reasonably good approximation for a tubular tire, but less so for a
clincher where the correct value may be something more complex (and
larger), and suggests to me that casing tension may be less in a
clincher compared to a tubular of equal pressure, which would
completely explain the anecdotal but widely reported difference between
clinchers and tubulars in their tendency toward bottoming out.