anonymous snipes:

Don't be a jerk, Brandt. I'm not repeating myth and lore, I'm
stating something that occured to me and threw out for
discussion.

Oh? "better shock absorption", "more comfortable ride", "lower
rolling resistance" are classics of pro-tubular speak and no
quantitative values or explanation how these things are achieved.
That is what myth and lore are made of!

What an ass. Proposing a hypothesis for discussion is not the same
as claiming something to be true; quantitative values are not
necessary, and I don't see you providing any, either.

Is it possible to discuss this without using rude epithets? The
response style suggests weakness of your position and lack of
perspective of the concepts involved.

No it doesn't. It applies a deserved label to you for your insulting
habit of insisting that anyone who questions you about anything, is
spouting "myth and lore".

What do you mean by "better shock absorption", "more comfortable
ride", "lower rolling resistance" and how are these produced by,
for instance, glue on the rim. You might notice that outside the
transition of tire casing to rim the two kinds of tire are
mechanically indistinguishable. Both are constrained to not absorb
any road displacements between the rim edges and both have a
circular cross section that can be deformed outside of that
diameter. It is not irrelevant that they are also visibly
indistinguishable, exactly because they are physically identical.

The tire "systems" are not physically identical as anyone can see
who picks them up and looks at them. Clinchers absorb road
displacements to the air inside them beyond the rim edge toward its
interior; tubulars practically do not.

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.

The difference in displacement is hidden inside the casing and the
rim. It is absurd to suggest that they are the same simply
because you can't see the difference.

You say that as though it were a secret or scientific mystery.
What is hidden inside the rim?

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?

The problem with your treatise there, in addition to being poorly
written and lacking "quantitative values", is the failure to
demonstrate that the change in pressure is insignificant. You
simply say it is and expect me to take your word for it, which is
pretty much the same method of argument that you always use, and,
ironically, accuse me of using. You present nothing more than
lore that may or may not be myth, but there is no way to know.

I think you don't understand vector forces and how they can be
separated into vertical and horizontal components.

I think I do.

Please demonstrate that rather than dodging with quips.

The analysis of tire casing forces is not a quantitative subject
but rather one of forces and their direction. Tire casings do not
support wheels in compression or bending but purely in tension,
similar to wire spokes in a bicycle wheel.

One thing that I'm pretty sure of is that a tire at 100psi does
not compress as far toward the rim as one at 50psi, so the air
pressure is doing something there that I don't see adequately
explained.

Read it again if you missed that. Casing tension varies with
pressure and rim support is given by casing tension.

Or rewrite it so that it is adequately explained.

You seem to be the exception when it comes to understanding what keeps
a wheel off the ground. I don't believe it needs a rewrite
considering how many people understand what it says. If you start
with incorrect beliefs and hold to them, you will have difficulty
understanding.

**** off, Brandt. You don't know how hard I ride.

You just explained that you don't get snake bites. I don't know
any active riders who have never gotten such a flat and I have seen
a lot of them.

I don't remember any circumstance where I had a flat on a tubular that
I could attribute to compression of the tire to the rim, except for
being squeezed once about 25 years ago into a curb by a car. And
despite what you say, there are few people on this ng that ride
tubulars regularly that have that type of flat with any regularity if
at all. 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. As I said, there were
no other tires but tubulars for the sport so we rode them wherever we
went and in those days many of the great roads in the Alps were yet
unpaved. I don't know anyone who rides tubulars today other than at
old timers meets where we try to pull out stuff from the old days.

So, again, **** off.

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

The term snake bite was coined at my Wednesday evening tubular
patch sessions in the 1970's when our local racers came to
patched flats.

We all know the lore of how you supposedly coined the phrase-
you've told us over and over again.

This only gets repetition when you do as though you never heard of it
or understand how it occurs.

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

You seem to have problems with that.

Do you repair tubular tires?

I think I said no, or at least very infrequently, anymore, below.
However, I have repaired many, many of them. The only tires I
remember as having punctures not attributable to outside punctures
were some steel (that's right, steel) belted Hutchinsons. Because
the problem ONLY occurred with them, and I never bought any more of
them, I believe it was a tire design issue, and at the time thought
it was likely that impacts were causing tube penetration by wires in
the steel belts. I admit it would indicate that with some frequency
I do bottom out the tire, yet I don't get pinch flats with the more
conventionally designed tubulars.

I don't understand what your are proposing here. Are you saying
that these people are not capable of measuring rolling drag?

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.

Your tests prove what they prove: 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
some unknown tubular, and that that advantage disappeared with the
better bond provided by track shellac.

Those are not unknown tubulars. I think your arguments fall in the
same bag as the denial that disc brakes pose a hazard as they are
designed today.

I have no opinion on disc brakes.

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:

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

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.

You seem to believe that tubulars at their peak use had something
that could be improved. Can you explain what those features are
and how they affect performance?

That would be a better question to ask Conti or Vittoria. For me,
the answer is I don't know, but would not be willing to make any
assumptions that nothing could be improved.

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.

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.

Vittoria has had glue but Mastik One? If so, did you use it? If
you didn't, and I'm pretty sure you used Clement, you used a vastly
inferior glue, which goes back to what I already said: you did not
quantify the quality of the glue or the gluing technique.

I used Tubasti and Pastali, Clement and Pirelli being a lower
temperature glue that tended to dry out in time.

But 3M should be replaced by Vittoria Mastik One. It has been
shown experimentally to be superior to 3M and every other glue
used for gluing tubulars in all characteristics that seem to be
important for a glue.

In what way is it superior.

Bond strength, heat resistance, time to achieve ridable bond
strength. Go read the test reports. I posted the reference already
in this thread.

Do you not believe that tubulars move on tacky road glue

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. 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? 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?

and that this is addressed by using hard glues for timed track
events?

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.

What conclusion do you find faulty and why?

I already answered that.

Repetition wouldn't hurt. I don't recall you giving an answer on that
anyway, most of which is in this thread right now.

I have not seen any bond strength comparisons.

That's because you didn't read the reports that I referenced.

Higher bond strength seems not to be desirable because tires cannot
be removed non-destructively, as you can read from people damaging
base tapes from excessively cured glue.

And which we have now determined was probably because they didn't
use the best technique for removing the tires, prying up a spot on a
tire, working the tool all the way under it, and then working the
tool around the rim. Once you get it going you may be able to pull
it the rest of the way off by hand, but you have to make sure you
are pulling up the base tape, not the casing. It is not that hard,
and it is certainly easier than trying to tear off by hand a tire
glued on that well. I have NEVER damaged a base tape removing a
tire.

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

The question is whether a strong soft glue such as Vittoria Mastik
One, applied properly with the minimal amount necessary to achieve
a secure bond, can approach the performance of shellac, and
perhaps even surpass the performance of shellac in your testing
(because the shellac performance in your testing may not have been
optimized).

If it is sticky and elastic it cannot be as low in losses as a
hardened adhesive that is hard to the extent of being brittle, as
shellac is.

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.

These tires were mounted by people who knew their business.

Wasn't their business clinchers?

Their business is tires and tubulars as well. These tests were not
done by desk clerks.

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 don't really see that anymore, but you present a strong argument
for using the minimal amount of glue necessary to provide a
strong, secure bond.

I don't understand what you mean by that. Are you saying that I
propose applying glue in a thick layer before mounting the tire?

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?

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.

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

You are retreating. 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.
If you use hardening glue, then there is no rim glue loss. So what?
The point is that tubulars glued with the conventional adhesives have
rolling losses that make them poorer in RR than the best clinchers.

That's all I ride for the last 30+ years except for a very
occasional mtb excursion. I don't patch them so much anymore,
though; I tend to use Tufo sealant or throw them away. I get very
few flats, so this system works for me without being wasteful.
How very very very few flats? Throwing away a tire that gets a
flat, is wasteful in my perception.

I don't throw away a tire that gets a flat, I try to fix it with Tufo
sealant which usually works. If it doesn't then I am likely to toss it
unless I think it otherwise worth saving. What I am saying is that the
combination of few flats and Tufo rarely leaves me in the position of
having to repair a flat the traditional way.

Please explain what is obsolete.

The glue.

I think if you read wreck.bike.tech you will see that riders still
use the glues furnished by tubular tire manufacturers and these are
no different from those used in the past.

That doesn't mean they are the best.

Just the same, why are you so fixated on glue? Look at the
results.

The glue is significant variable in the results, but unfortunately
you only used two (Clement? & shellac).

I never used shellac. I only pointed out that after seeing the test
results I finally discovered why there is hard glue. You
should realize that until these curves were shown, no one in bicycle
racing or the industry could explain why there was hard glue. All
they said was that rolling a tire on a track was a greater possibility
if hard glue was not used.

Do your base tapes wear in the course of riding a tire through to
the cords or not? I regularly ride my tires until the cords show,
now and in my days on tubulars.

Sadly, I don't. Something else catastrophic usually happens first.

It seems you may also believe most physics is obsolete, much of
the research having been done more than a century ago. Poor
Galileo doesn't rate highly in your science!

And in fact much of it is obsolete, being usable to provide rough
explanations of only phenomena that are directly observable with
the human senses. But, of course, this is really beside the point
since your comment has no purpose other than to belittle and
amuse.

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

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. Attack the messenger, not the message.

Jobst Brandt