The old tubular vs. clincher debate - some evidence?

[Jens]

I posted this over on biketechreview.com. But I know you
lot love this topic too. ;-

I was testing out some rollers today. I couldn't
resist a little comparison. I tried a 404 with a
Conti-glued veloflex carbon and a Hed Alps clincher
with a Vittoria Ks, both inflated to 120 psi.
Here are the trials, in order:

1) 30.6 mph, 128 watts
2) 30.8 mph, 125 watts
3) 30.7 mph, 136 watts
4) 30.6 mph, 138 watts
5) 30.8 mph, 125 watts

Each trial was 1-3 minutes and was started a while
after the target speed was reached. Power measurement
was with an SRM Pro.


-- Jens

 

[Jens]

I forgot to mention.....I wanted to leave it up to you lot to guess
which
trials are for which tire. ;-)

 

[Phil, Squid-in-Training]

Jens wrote:
> I forgot to mention.....I wanted to leave it up to you lot to guess
> which
> trials are for which tire. ;-)

Anything above 130, Vittorias. Below 130, Veloflex.

Okay, debate settled. Who wants to go out for free burgers? Everything's
on me!

--
Phil, Squid-in-Training

 

[Wayne Pein]

Jens wrote:

> I forgot to mention.....I wanted to leave it up to you lot to guess
> which
> trials are for which tire. ;-)
>

Since the wheels are also different, this experiment is not able to make
any inferences on tire performance.

Wayne

 

[Jens]

Wayne Pein wrote:
> Jens wrote:
>
> > I forgot to mention.....I wanted to leave it up to you lot to guess
> > which
> > trials are for which tire. ;-)
> >
>
> Since the wheels are also different, this experiment is not able to make
> any inferences on tire performance.
>
> Wayne


Do you have some suggestions as to putting
clinchers on tubular rims?

The Alps and the 404 are very similar with regard to
spoke count and rim depth. Their drag figures,
as independently tested, are very similar.

--jens

 

[Kinky Cowboy]

On Wed, 05 Oct 2005 22:17:30 GMT, Wayne Pein <[email protected]> wrote:

>Jens wrote:
>
>> I forgot to mention.....I wanted to leave it up to you lot to guess
>> which
>> trials are for which tire. ;-)
>>
>
>Since the wheels are also different, this experiment is not able to make
>any inferences on tire performance.
>
>Wayne

Spoke count is the same 18f 24r, but it would be nice to see the spoke
cross sections the same too. On rollers, rim shape seems largely
irrelevant, but surface area still matters, and of course different
rim depths (58mm Zipp vs. 50mm HED) also affect spoke length. That
extra 8mm of spoke, at the fast moving end, could account for more
than the tyre difference. Since both wheelsets are available in both
tubular and clincher formats, Jens needs to buy only one pair of new
wheels to convince us
Kinky Cowboy*

*Batteries not included
May contain traces of nuts
Your milage may vary

 

[Andrew F Martin]

Considering the fact that the variables you introduced (different
wheels) likely far outweigh the statistically significant data points
that you chose - guessing values is a complete crapshoot. If you
re-ran this test with 32hole clincher and tubular wheelsets both setup
with Mavic Reflex Tub/Clinch Rims (for example) with consistent
rim/spoke profiles - I'd imagine you'd find somewhat more comparable
values. You also need to factor in your wattage estimates - what tools
are you using to determine these numbers and factor in their relative
margin for error and you start reallizing that to make any sort of a
point here - you must have a far more controlled environment with more
consistent test setup.

What's too bad is that I'm sure some manufacturer would find your study
sufficient to tout their product as "the best" and run with it.

Interesting way to spend the afternoon - yes, scientific - no.
-a

 

[Jens]

Phil, Squid-in-Training wrote:
> Jens wrote:
> > I forgot to mention.....I wanted to leave it up to you lot to guess
> > which
> > trials are for which tire. ;-)
>
> Anything above 130, Vittorias. Below 130, Veloflex.
>
> Okay, debate settled. Who wants to go out for free burgers? Everything's
> on me!
>
> --
> Phil, Squid-in-Training


Sorry! Do I still get a hamburger? I'd like mine
with cheese and a great big portebello mushroom.


-jens

 

[Jens]

I forgot to add, I failed to adjust the speed for the greater size
of the 23c Vittorias. They roll out almost 2cm longer than the
Veloflexes. So the difference is even greater than what those
data reflect.

The variance is also probably less. I should have thrown out
the first run, because I adjusted the front wheel stand after
it.

So you think there's 10+ watts of aerodynamic differences
between a Hed Alps and a 404? I'll bet josh at zipp would
beg to differ.


- jens

 

[Jens]

Andrew F Martin wrote:
> Considering the fact that the variables you introduced (different
> wheels) likely far outweigh the statistically significant data points
> that you chose - guessing values is a complete crapshoot.

Really? 11+ watts. That's seems pretty significant. BTW,
others have duplicated this in similar tests. In one case,
the clincher was on a regular spoked wheel and the tubular on
a 404. The clincher still won -- handily.


If you
> re-ran this test with 32hole clincher and tubular wheelsets both setup
> with Mavic Reflex Tub/Clinch Rims (for example) with consistent
> rim/spoke profiles - I'd imagine you'd find somewhat more comparable
> values. You also need to factor in your wattage estimates - what tools
> are you using to determine these numbers and factor in their relative
> margin for error and you start reallizing that to make any sort of a
> point here - you must have a far more controlled environment with more
> consistent test setup.

The 4-strain gauge SRM Pro has stated accuracy of +-2%. I have
the 8-strain gauge Pro DA version. The accuracy is probably
better than that.


-- Jens

 

[[email protected]]

Jens Kheycke writes:

> I posted this over on biketechreview.com. But I know you lot love
> this topic too. ;-

> I was testing out some rollers today. I couldn't resist a little
> comparison. I tried a 404 with a Conti-glued veloflex carbon and a
> Hed Alps clincher with a Vittoria Ks, both inflated to 120 psi.
> Here are the trials, in order:

> 1) 30.6 mph, 128 watts
> 2) 30.8 mph, 125 watts
> 3) 30.7 mph, 136 watts
> 4) 30.6 mph, 138 watts
> 5) 30.8 mph, 125 watts

> Each trial was 1-3 minutes and was started a while after the target
> speed was reached. Power measurement was with an SRM Pro.

"in order"? What order and which tire? If you can re-run the
experiment with inflation pressures at 120, 110, 100, 90, 80,70, 60,
50psi for each tire, we would have a better impression of the accuracy
of measurement, knowing that a smooth curve drawn through the data
points will show the variance and the true characteristic of the tire.

Interestingly, you may have seen that clinchers of different quality
(TPI aka casing thickness) are mainly multiples of other tires tested.
The family of curves in the set done by IRC are this way except those
with significant tread profiles.

Tubulars with road glue will show their characteristic but with an
offset from their true position due to rim glue losses and will not be
a direct multiple of clincher tires. By their slope, it is apparent
that they belong below the other tires but that they have an offset
from that position.

See:

http://www.terrymorse.com/bike/imgs/rolres.gif

Jobst Brandt

 

[Kinky Cowboy]

On 5 Oct 2005 15:34:15 -0700, "Jens" <[email protected]> wrote:

>
>Wayne Pein wrote:
>> Since the wheels are also different, this experiment is not able to make
>> any inferences on tire performance.
>
>
>
>The Alps and the 404 are very similar with regard to
>spoke count and rim depth. Their drag figures,
>as independently tested, are very similar.
>
>--jens

In rolling road, wheel moving forward tests, they might be similar.
There is no reason to suppose that such similarity would be carried
forward to the completely different airflow conditions which pertain
on rollers.

There is also the tyre question to consider - to get any kind of
meaningful comparison, the two tyres must be of identical construction
with the exception of their means of mounting to the rim - by choosing
tyres from different manufacturers, you have completely eliminated any
possibility of assessing the relative merits of the two mounting
methods.

Kinky Cowboy*

*Batteries not included
May contain traces of nuts
Your milage may vary

 

[Jens]

OK. Here you go....
The columns are PSI, Power in Watts, Speed in MPH.


Vittoria Evo Ks (Clincher) on Alps
120 119.8 30.75
100 123.9 30.71
90 126.5 30.75
80 130.3 30.74
70 135.0 30.75
60 138.5 30.57

Veloflex tubular on Zipp 404
120 133.3 30.67
100 136.9 30.67
90 135.8 30.69
80 137.3 30.66
70 141.8 30.61
60 146.9 30.71

Vittoria Evo Ks (Clincher) on Weyless Korsa
120 115.3 30.91

The last test was for those who think the wheel makes
a big difference. I used the same model tire and the
same tube on a $60 "Weyless" wheel with 20 bladed
spokes. The tire was newer than the one on the Alps,
which might account for some of the difference.


-- Jens

 

[Jens]

BTW, the original order was

> 1) 30.6 mph, 128 watts KS clincher
> 2) 30.8 mph, 125 watts KS clincher
> 3) 30.7 mph, 136 watts Veloflex tubular
> 4) 30.6 mph, 138 watts Veloflex tubular
> 5) 30.8 mph, 125 watts KS clincher


-- jens

 

[Jens]

BTW, the original order was

> 1) 30.6 mph, 128 watts KS clincher
> 2) 30.8 mph, 125 watts KS clincher
> 3) 30.7 mph, 136 watts Veloflex tubular
> 4) 30.6 mph, 138 watts Veloflex tubular
> 5) 30.8 mph, 125 watts KS clincher


-- jens

 

[Andrew F Martin]

Strange that your Korsa wheel ranked the best...The more data points
show more obvious trends which are quite interesting. I don't run
Veloflex tubulars, but rather Vittoria Corsa KX (?) tubulars. I do run
the Evo K's for my training wheelset - so maybe I'm wasting precious
watts (seemingly quite a few - I imagine as I get closer to LT wattage
numbers, that delta is bigger) using tubulars.

Perhaps I need to do similar tests to see where else I can steal some
free watts...

 

[Jens]

Kinky Cowboy wrote:
>
> In rolling road, wheel moving forward tests, they might be similar.
> There is no reason to suppose that such similarity would be carried
> forward to the completely different airflow conditions which pertain
> on rollers.
>
> There is also the tyre question to consider - to get any kind of
> meaningful comparison, the two tyres must be of identical construction
> with the exception of their means of mounting to the rim - by choosing
> tyres from different manufacturers, you have completely eliminated any
> possibility of assessing the relative merits of the two mounting
> methods.
>
> Kinky Cowboy*
>

Actually what I did was choose the tubular (Veloflex carbon) that
had the very lowest rolling resistance in the German "Tour" magazine's
test of tubular tires. No, they didn't test Dugast, but they did
test Continental, Gommitalia, Tufo, Veloflex, and Vittoria.

So the Vittoria Evo clincher tests better than the Veloflex Carbon
tubular, which test much better than the Vittoria tubular. Is
that good enough?


-- jens

 

[John Forrest Tomlinson]

On 6 Oct 2005 12:54:41 -0700, "Jens" <[email protected]> wrote:

>
>Kinky Cowboy wrote:
>>
>> In rolling road, wheel moving forward tests, they might be similar.
>> There is no reason to suppose that such similarity would be carried
>> forward to the completely different airflow conditions which pertain
>> on rollers.
>>
>> There is also the tyre question to consider - to get any kind of
>> meaningful comparison, the two tyres must be of identical construction
>> with the exception of their means of mounting to the rim - by choosing
>> tyres from different manufacturers, you have completely eliminated any
>> possibility of assessing the relative merits of the two mounting
>> methods.
>>
>> Kinky Cowboy*
>>
>
>Actually what I did was choose the tubular (Veloflex carbon) that
>had the very lowest rolling resistance in the German "Tour" magazine's
>test of tubular tires. No, they didn't test Dugast, but they did
>test Continental, Gommitalia, Tufo, Veloflex, and Vittoria.

No Schwalbe?

JT

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[Jens]

John Forrest Tomlinson wrote:
> >
> >Actually what I did was choose the tubular (Veloflex carbon) that
> >had the very lowest rolling resistance in the German "Tour" magazine's
> >test of tubular tires. No, they didn't test Dugast, but they did
> >test Continental, Gommitalia, Tufo, Veloflex, and Vittoria.
>
> No Schwalbe?
>
> JT
>

Sorry. I forgot. They did Schwalbe tires too. They nearly
tied the Tufos for being the very worst.


-- Jens

 

[David L. Johnson]

On Wed, 05 Oct 2005 14:57:17 -0700, Jens wrote:

>
> I posted this over on biketechreview.com. But I know you
> lot love this topic too. ;-
>
> I was testing out some rollers today. I couldn't
> resist a little comparison. I tried a 404 with a
> Conti-glued veloflex carbon and a Hed Alps clincher
> with a Vittoria Ks, both inflated to 120 psi.
> Here are the trials, in order:
>
> 1) 30.6 mph, 128 watts
> 2) 30.8 mph, 125 watts
> 3) 30.7 mph, 136 watts
> 4) 30.6 mph, 138 watts
> 5) 30.8 mph, 125 watts

which was with which wheel? You have two wheels, and 5 tests. I can't
put them in any order.


--

David L. Johnson

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