Magnitude of losses from tubulars in terms of rolling resistance

[[email protected]]

I was recently turned to some postings on slowtwitch.com regarding Tufo
tubulars (with tape), and how they have dramatically higher rolling
resistance than both other tubulars and clincher wheels. Besides
citing some German magazine article where the tires were tested, there
is a member claiming that they train with a power meter and reported
20W difference between using their wheels with Tufo tires and a set of
decent clinchers. Others on the board are reporting equally disturbing
anecdotal evidence that Tufo tires are bad.

I used a set of LEW Palermos with Tufo tubulars (and tape) as my race
wheels last season, and having read these postings on slowtwitch, I'm
almost afraid to continue using them. I train with a PowerTap . . .
20W is a lot.

I know there are people on this group (Jobst Brandt, perhaps others as
well) that are experts on this topic. I accepted their statements that
the rolling resistance of tubular tires was more than for clinchers,
but always figured the effect was more or less negligible. Is this 20W
statement possible?

Additionally, I see from some posts that there is a recommendation to
use "track glue" instead of standard tubular glue . . . glue that is
harder offers lower rolling resistance. Is there any specific brand of
this type of glue?

 

[[email protected]]

I'm not an expert. You could use shellac but this is only available in
hardware stores. You would have to remove all the glue from your rims
as shellac and tubular glues don't get along. Tire replacement would
be a royal pain as one of the reasons one uses tubular glues is to make
tire changing possible while on a road ride. Who knows what the
wattage figure would be for you and your equipment. One of the
posters also said he got better rolling resistance from Vittoria Corsa
tubulars than the clinchers IIRC. YMMV.

 

[bikeguy11968]

So they are saying that the TAPE makes losses of 20w?? I dunno....
Seems a little wacky to me. I do use tufo's myself, adn I will state
unequivocally that the s22 training tyre is the slowest tyre made by
mankind. Our freaking juniors coast downhill faster than I do.. Those
things roll S-L-O-W. But they corner well and are bombproof, hence
training tyre. The s3 lites are damn fast.. I don't use tape, except
for cross, and even then it's with glue as well.

A few years ago, I got some Nisi (?) rim cement, that was JKA approved.
Cost a fortune for the shop, and came in 2 bottles.. A bonding agent,
and a hardener. THAT stuff stuck like nobody's business.. Typically I
use mastik 1. I seem to recall the problem with LEW and TUFO was one
of rim/tyre interface. Paul had a really shallow rim surface that
didn't mate well with tufo tyres. We did use tufo's on them at times,
but we are better at gluing tyres (knock on wood) than the average
bear. And we check them frequently. I do recall that the 19mm tyres
stuck better to the super shallow super narrow lew rim.
MYLES

 

[bikeguy11968]

So they are saying that the TAPE makes losses of 20w?? I dunno....
Seems a little wacky to me. I do use tufo's myself, adn I will state
unequivocally that the s22 training tyre is the slowest tyre made by
mankind. Our freaking juniors coast downhill faster than I do.. Those
things roll S-L-O-W. But they corner well and are bombproof, hence
training tyre. The s3 lites are damn fast.. I don't use tape, except
for cross, and even then it's with glue as well.

A few years ago, I got some Nisi (?) rim cement, that was JKA approved.
Cost a fortune for the shop, and came in 2 bottles.. A bonding agent,
and a hardener. THAT stuff stuck like nobody's business.. Typically I
use mastik 1. I seem to recall the problem with LEW and TUFO was one
of rim/tyre interface. Paul had a really shallow rim surface that
didn't mate well with tufo tyres. We did use tufo's on them at times,
but we are better at gluing tyres (knock on wood) than the average
bear. And we check them frequently. I do recall that the 19mm tyres
stuck better to the super shallow super narrow lew rim.
MYLES

 

[[email protected]]

No. There are a couple of riders who use clinchers wheels and tubular
wheels on the same routes and claim that to maintain the same speed on
tubulars requires 20 more watts of output versus the same speed on
clinchers. Invariablly the tubular/wheel combination is lighter and
more aero than the clincher/wheel combination. Most folks are using a
higher quality Tufo, not the S22.

http://forum.slowtwitch.com/gforum....view=forum_view_collapsed;;page=unread#unread

http://forum.slowtwitch.com/gforum....view=forum_view_collapsed;;page=unread#unread

 

[JeffWills]

[email protected] wrote:
>
> Aha! Here's the result of one test using Tufo tires:
>
> "We also tested the tufo tires. They seemed like the perfect
> solution. They could take ridiculous amounts of pressure.
> Because they are rolled in there construction rather than
> sewed they are the most round and uniform tire I've ever
> seen. They also have sturdy side walls and are reasonably
> inexpensive. Seems perfect right? One big flaw, slow as
> molasses. I was as much as 4 mph slower on these tires even
> at 200psi."
>
> "I spent a few days trying to top 96km/h in Montreal. I
> switched to the panaracers and immediately went 101km/h
> several times. This was shown in our rolldown test as well
> when I rolled nearly 50% further on the cheap panaracers.
> Even On my road racing bike I could feel that the tufo's
> where sluggish."
>

I reread the article- that quote is from Sam Whittingham, the World's
Fastest Human (tm). Sam's pretty good about preparation and testing,
and I value his assessments. The HPV's he races usually roll on 24"
Panaracer Tecnova clinchers- good, but not great tires. If the Tufos
make a 5 km/h difference at those speeds (where air drag dominates),
then the Tufos are pretty crappy.

Jeff

 

[Qui si parla Campagnolo]

[email protected] wrote:
> I was recently turned to some postings on slowtwitch.com regarding
Tufo
> tubulars (with tape), and how they have dramatically higher rolling
> resistance than both other tubulars and clincher wheels. Besides
> citing some German magazine article where the tires were tested,
there
> is a member claiming that they train with a power meter and reported
> 20W difference between using their wheels with Tufo tires and a set
of
> decent clinchers. Others on the board are reporting equally
disturbing
> anecdotal evidence that Tufo tires are bad.
>
> I used a set of LEW Palermos with Tufo tubulars (and tape) as my race
> wheels last season, and having read these postings on slowtwitch, I'm
> almost afraid to continue using them. I train with a PowerTap . . .
> 20W is a lot.

Is it really? I think claims of good and poor rolling resistence, altho
when taken in isolation seem huge, when applied to the bike/rider
equation, are lost in the noise.

Not a fan of Tufos since ya can't repair them, but tubies in general
have lots of advantages, none related to rolling resistence. In the sea
of race wheels, many are carbon and tubie, so a good choice of tubie is
essential.

>
> I know there are people on this group (Jobst Brandt, perhaps others
as
> well) that are experts on this topic. I accepted their statements
that
> the rolling resistance of tubular tires was more than for clinchers,
> but always figured the effect was more or less negligible. Is this
20W
> statement possible?
>
> Additionally, I see from some posts that there is a recommendation to
> use "track glue" instead of standard tubular glue . . . glue that is
> harder offers lower rolling resistance. Is there any specific brand
of
> this type of glue?

I use tubies everyday(not a racer) and we glue tubies for many racers
here in the republic. Using regular tubie glue, from Conti or Vittoria,
done correctly, makes for a tire that will not roll off inna race, the
goal, after all. For durability, Conti Sprinters, for a more supple
ride, Vittoria CX...

 

[[email protected]]

Yes, 20W is a lot. The question isn't whether losing 20W can
measurably slow you down -- anyone who trains with a powermeter will
tell you they'd pay an awful lot to add 20W to their threshold.

The question is whether the Tufos can really suck that bad as to take
an extra 20W to roll at race speeds. Whether they are really that bad
or not, I've seen enough from this thread and others that makes me
doubt them. I'm going to make a switch . . . just got some Veloflex
Records.

Thanks for all of the replies.

 

[[email protected]]

[email protected] wrote:
>
> Tom Compton used Jobst Brandt's rolling resistance data from
> a few decades ago to create this calculator, which lets you
> compare a variety of kinds of tires:

Yes, indeed, a few decades ago. The recent papers published on the bond
strength of tubular glue show that Vittoria Mastik and Continental
glues are much stronger than the common glues of that period, such as
3M FastTack. Furthermore, even though Jobst's tests were designed to
compare clinchers' and tubulars' rolling resistance and *not* to
determine the method of gluing tubulars that produces the least rolling
resistance, if you can extrapolate anything from the comparison of the
two glues used it would be that tubular rolling resistance is a
function (among other things) of how well the tire is glued to the rim.
And, since we don't know how well the tires were glued to the rim in
Jobst's test, (not to mention the fact that the tests were sponsored by
a clincher manufacturer), we really can't say *anything* from Jobst's
tests about how well an optimally glued tubular will perform with
contemporary road glues.

Furthermore, it was noted last year that LA specifies handmade tubular
silks for racing in the TDF. If anyone has ever read anything about the
performance testing he demands of his equipment, you would probably
find it inconceivable that he uses tubulars out of some superstitious
belief in their qualities, especially since his tire sponsor would
probably rather see him on clinchers since they are the mainstay of
Hutchinson's bicycle tire business. I'm also pretty sure that LA's team
won't be releasing the results of their tire performance testing.

Overall, cheap TUFOs aside, I think it is just as likely that tubulars
are higher performing than clinchers as it is the other way around. It
is at least as ridiculous to take a couple of extremely flawed tests,
extrapolate the hell out of them and create new cycling "lore" as it is
to take as gospel the lore based on decades of experience of
professional cyclists.

 

[[email protected]]

Dear Carl,

You don't really know why pros ride tubulars. You are supposing. You
could be right, you could be wrong.

> (As mentioned in another current thread, pure rolling
> resistance doesn't apply in the real world. Higher pressures
> reduce pure rolling resistance as measured by drums,
> low-speed rolling tests, and metered trainers, but pressures
> closer to 100 psi roll faster on real pavement than
> pressures closer to 170 psi because the stiffer tires bounce
> so much more on the road surface that they waste power
> jiggling the rider up and down. On smoother tracks, the
> bouncing is reduced, so higher pressures pay off.)

In other words, you're saying that on real world road courses, tubulars
have lower (or at least insignificantly different even to a competitive
cyclist) effective rolling resistance. I think you might be right. Or
not.

> Given the layer of glue and tape between the tubular and the
> rim, it seems quite reasonable to predict that pure rolling
> resistance would be higher in a tubular than in a clincher
> constructed of the same materials.

It is quite reasonable. I would also suggest that it would be equally
reasonable to predict that a well glued tubular stabilized against the
rim across its entire base tape would have lower rolling resistance.
And in fact, the tests seem to bear this out- tubulars glued with track
shellac in Jobst's tests match the rolling resistance of the clinchers.
And from there, it is also reasonable to predict that with some
experimentation on gluing technique with contemporary glues, *maybe*,
decades later, the rolling resistance of tubulars could be even further
improved.

> (Obviously, a hand-made
> tire sparing no expense and intended to last a single day is
> not comparable to a mass-production tire.)

No pro would ride a tubular that is only intended to last one day.
There is no doubt that silks provide stronger casings than tubulars of
equivalent weight made of other materials. Whether they would have
inherently lower rolling resistance, who knows? (And a handmade,
quality commercial tubular is not exactly a mass-production tire.)
Maybe threadcount is important to reducing rolling resistance.

> The higher-rolling-resistance prediction about tubulars is
> supported by the original poster's comment about riders
> using Tufo sorta-tubulars on metered trainers and finding 20
> watts higher measured pure rolling resistance.

Which is it, real world rolling resistance is better in tubulars or 20
watt deficit? If the former, case closed; if the latter, I'm saying LA
is not going to give up 20 or even 10 watts for the sake of tradition

> While I sometimes question Jobst's explanations, I rather
> doubt that he performed misleading tests of a number of
> tires. His explanation in this case seems quite reasonable.

It is reasonable given its parameters. But as I have pointed out
repeatedly there is no control for gluing technique and there is no way
to extrapolate the performance of those glues to Vittoria Mastik. His
tests were not designed to mislead, but they weren't designed to
optimize the performance of the tubulars, either.

> And given Jobst's considerable experience riding on tubulars
> before good clinchers became available, I expect that he
> knows how to glue tubulars to rims.

By his own standards, he does not. His knowledge of gluing was "lore",
not based on any experimentation designed to optimize the process.

> In any case, there must
> be an energy-wasting layer of glue between the tubular and
> the bicycle, no matter who does the gluing.

So how squirmy would you expect a tubular to be on rim with no glue at
all? More or less rolling resistance? I'm guessing that compared to
nothing, glue *reduces* rolling resistance! You are making an
assumption that really has not been experimentally verified- that a
contemporary road glue is inherently the source of rolling resistance
compared to a clincher. I am suggesting an alternative variable as
being the real predictor- the amount the tire is able to squirm with
relation to the rim. So then the question with regard to glue is how
well it restricts such movement.

> Do you know of any plausible method for gluing tubulars to
> rims that increases rolling resistance so much more than
> usual that it turns them into slugs instead of speedsters?

Too much 3M FastTack or too little 3M FastTack, although your
requirement that they be "slugs" is absurd because there is not that
much variance to play with.

> Any method that you suggest should also be able to preserve
> the difference between track and road glue in testing.

A ridiculous and artificial constraint, but there must be an amount of
track glue where it is either too much or too little such that rolling
resistance is increased.

> Do you know of any test data that contradicts Jobst's
> testing? That is, are there any rolling resistance tests
> that show the advantage that you predict for tubulars?

I'm not predicting anything; I'm only saying that his tests are too
significantly flawed to make the sweeping assumptions that have been
based on them. I *did* suggest that there is a high probability that
LA's team does have such data, but that is only supposition.

> You might be able to do some testing of your own by using
> clinchers and tubulars on a metered trainer.

I'll be out riding my bike (tubular equipped) instead. I'll leave the
testing to those with more at stake than me, but in the meantime I'll
just point out that we don't have any answers and we should stop
pretending that we do. Personally, I would not use cheap Tufos, I would
use a high quality tubular tire and make sure that it is glued on
carefully and tightly with Vittoria Mastik, if I was looking for
maximum performance (not to mention safety from heat resistance and
convenience from quick set up time).

Uncertainly yours,
John Lydon

 

[[email protected]]

On 11 May 2005 12:59:45 -0700,
[email protected] wrote:

[snip]

Dear John,

If you have any reason based on physics why a tubular with a
layer of glue between it and the rim should not have more
rolling resistance than a clincher of similar material and
thickness, please share it with us.

A physical explanation would be more convincing than
speculating without any evidence that Jobst rigged tests.

As for Armstrong, he's like most pros--he hardly chooses
tires solely on the basis of rolling resistance.

Unlike Armstrong and all the other teams, Hamilton's team
chose to use narrower tubulars (not even clinchers) on one
rough Tour de France stage in 2004, hoping that a slight
edge in rolling resistance or reduced wind drag would help
them win.

Five flat tires and three crashes reminded the Phonak team
that there's more to tires than rolling resistance:

http://www.velonews.com/tour2004/tech/articles/6484.0.html

The amazing thing was that Hamilton's team still managed to
finish so well.

Carl Fogel

 

[[email protected]]

[email protected] wrote:

> If you have any reason based on physics why a tubular with a
> layer of glue between it and the rim should not have more
> rolling resistance than a clincher of similar material and
> thickness, please share it with us.

Any layer of glue that provides a sufficiently tight bond to allow no
more tire squirm no more than a clincher meets your criterion.
According to Jobst's tests that glue is shellac. It would probably be
any glue which, when applied optimally, has less squirm than the tire
itself and bonds the tire tightly to the rim.

> A physical explanation would be more convincing than
> speculating without any evidence that Jobst rigged tests.

I didn't say that Jobst rigged the tests and you know it, which makes
you a liar. I didn't speculate, I stated a fact: to repeat, Jobst's
tests were not designed to find the optimal gluing technique that would
produce the lowest rolling resistance for tubulars. And to suggest now,
twenty or so years later, that he did use the best possible technique
with the best possible glue (which didn't even exist at the time) is
just plain stupid, and I don't think you're stupid.

> As for Armstrong, he's like most pros--he hardly chooses
> tires solely on the basis of rolling resistance.

You don't know what the criteria are that he uses (and he is NOT like
most pros or ANY other pros), but it almost certainly is some
calculation that determined that he gets a competitive advantage from
the tires he uses- he clearly demands that his sponsors provide him
with equipment that not only is competitive, but gives him an advantage
if at all possible.

> Unlike Armstrong and all the other teams, Hamilton's team
> chose to use narrower tubulars (not even clinchers) on one
> rough Tour de France stage in 2004, hoping that a slight
> edge in rolling resistance or reduced wind drag would help
> them win.

So what's your point? If TH was choosing tires for a reduction in
rolling resistance why didn't he choose clinchers?

> Five flat tires and three crashes reminded the Phonak team
> that there's more to tires than rolling resistance:

But we're talking about rolling resistance and you just stated that TH
chose tubulars over clinchers for their advantage in rolling
resistance. Are you suggesting that tubulars with better grip have more
rolling resistance than clinchers with equivalent grip, while track
tubulars have less rolling resistance than clinchers with equivalent
grip? Because if you're not suggesting that (and it would be utterly
wild speculation if you were), all you have done is offer confirmation
of what I said was a possibility- that pros think tubulars can offer an
advantage in rolling resistance.