its tought to get real data, because I could compare my Mavic Open Pro with PT Pro and Clinchers to my Tubbie 404 with PT SL and tubulars, but that gives waaaay too many variables. Perhaps if someone out there has a clincher 404 with PT SL and lives near me then we could meet up and run a test, but unless someone has done a test with the "same" wheel, then there is so much speculation.

FWIW, I don't care too much about the whole pinch flat argument or the flatting 2 miles from transition argument.

perfect, thanks for complying with my request...

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USA Triathlon Level 3 Elite Coach
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Actually, my first response was the weight issue. Zipp 404 Clincher with a GP 4000 is going to weigh about 522 grams MORE than a Zipp 404 Tubular with Competition 22's. That is a little more than pound, which falls in line with my original assertion that UP TO a couple of pounds could be saved with tubulars. SO, because I am a weight weenie, for me it is weight issue, and now I've provided DATA to back it up.

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Geoffrey Nenninger

Wow...I didn't realize tubulars were still rideable at over 20 mph when they were flat. I knew they were rideable, but I assumed it would be something like 10-12 mph...

I got a flat on my 404 tubular wheel the day before the ITU race in Honolulu last month. I would not have been able to ride it at 20+mph (maybe in a race I'd have thrown caution to the wind) but I ended up walking it as even at 10-12 mph it felt like I would have damaged my rim.

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Geoffrey Nenninger

And I've watched a teammate ride a flat FRONT clincher at speeds of over 20mph with little difficulty. He was even riding down a twisty descent at the time...it was squirrelly, sure...but so would a flat tubie be as well.

Just thought I'd add a conflicting anecdote...BTW, the plural of anecdote is NOT data. ;-)

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http://bikeblather.blogspot.com/

Actually, my first response was the weight issue. Zipp 404 Clincher with a GP 4000 is going to weigh about 522 grams MORE than a Zipp 404 Tubular with Competition 22's

What?

ZIPP 404 clincher rear, 884 continetal gp4000 204g, continental 60mm stem tube 90g

ZIPP 404 tubular rear, 682, continental competition tubular 275g.

Difference 221 grams

Anything else?

The study noted that the rolling resistance improved significantly for the Tufo tires with inflation pressures above 140psi, but failed to quantify it and include it in the table.

Also, the comfort level was not really quantified as it was based solely on inflation pressure. Certainly some tires are more comfortable than others at any given pressure.

Also notice that the tubular tires that performed the best within the parameters of the test were those inflated closer to their maximum inflation values.

Finally,

If we're going to use tubulars--we should run them at higher pressures.

[reply] You see that every time at the big cyclocross races. Don't see any advantage ever with clinchers in cyclocross.[/reply]
I've rolled a tubular in cyclocross - even with the best glue job, the low pressure is the killer on some rim/tire combinations.
The advantages of clinchers for non pros -
- you never again have to smell or cleanup tubular glue, or have to waste a nearly new tire/glue job due to a mishap with the tire on one of the first rides
- if you are a lightweight, you don't need tubulars to avoid pinch flats
- you don't need to own multiple sets of wheels and tires for different course conditions, just different tires.

I am note sure about this but can you even get a 19m clincher for your front wheel? I run a Conti Competition 19 up front and 22 in back based on recommendations from Hed. They told me the improved aerodynamics of the 19 outweigh the higher RR for a front wheel. Makes sense when you consider the wheel rim is around 19 as well.

As for data, I have never flatted on a tubular during a race after 12 years of racing. I will admit I have not submitted this for peer review yet…

Why do you think you can't use your wheels to test this out? To make an "apples to apples" comparison tirewise, throw an Open Corsa on that Open Pro and go find yourself a hill to climb. The aerodynamics of the rear wheel difference will be extremely miniscule under that condition. If you're worried about the weight difference, just add a water bottle when you use the tubular to compensate for the slight difference.

Here's the easy way to do it. Do constant power runs up the hill over a set distance. Afterwords, grab the ave power and ave speed and trot on over to analyticcycling.com. Enter in all the necessary variable into the "Power given Speed" calculator. Assume a set Crr of .0050 and see what the calculator estimates for the power of each run and compare it to the actual power. You should then be able to see which wheel takes more power and be able to make your decision wisely.

Oh yeah...do a "stomp" test on your wheels prior to the test and make sure the offset is zeroed.

Have fun!

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http://bikeblather.blogspot.com/

The wheel and tire end of the bicycle industry make tubulars as a practical joke. Whenever a customer or pro team chooses to use tubulars they all have a good laugh about it, because clearly, clinchers are far superior. It's confirmed by all the testing.It's the same thing with wheelsize; 700c wheels are far superior but they throw a few 650c wheeled bikes into the pipeline just for laughs. Watch out for aerodynamic and weight issues too, because these are obviously part of the conspiracy as well. The biggest one of all though, is coaching and training advice.Who would do anything other than the correct type of training authorized by the all-knowing coach, of which there is obviously only one? You can never expect to perform well if you don't exactly according to "The Program".

How do you find all this valuable information? It's only dispensed by the people who have total authority and confidence in these matters. They accept no latitude on any issues as only they have the answers. Ask for it and they'll step up, as they miss no opportunity to impart their knowledge upon others. You know who they are.

Greg.

Right...and I was responding to your assertion that the pinch flat "issue" was the most important part of your response.




Finally! Data! However, I'm sad to say that you may be a bit high on the weight difference. I've run the numbers on 404 clinchers vs. 404 tubies (using "apples to apples" tires - Vittoria Corsas and Open Corsas, latex tubes, and rim strips) and I got a weight difference much closer to 450 g (or, 1 lb. Hence my assertion that the weight diff was closer to 1 lb than to "a couple").

While I also tend towards "weight weenie-ism" in bicycle equipment, in this case your "weenie-ness" may be somewhat misplaced. Obviously, the trade-off here is weight vs. rolling resistance. By going with the lighter wheels you're required to take a hit on rolling resistance. If you're going to be racing on flat terrain, the obvious choice is going to be to use the setup with the lower RR, right? Conversely, if you're hitting hilly terrain, the best choice is going to be the lighter setup, right?...Well, not so fast.

Logically, there is going to be a certain steepness of hill where the better rolling resistance of the clincher setup will be offset by the lighter weight of the tubulars, correct? Anything less steep and the clinchers will have an advantage (due to their RR), and on anything steeper the tubular setup will win out (due to their lower mass). OK, so what is that steepness?

If you run the numbers (I have...it's basic physics) you'll find that "break even" point to be over 9% grade! That's right...at every grade below that, the clincher version of the 404 will be faster. Now...that's comparing one of the best rolling clinchers to it's tubular "twin", which also happens to be one of the best rolling tires of _its_ type. If you are running slower tubies (i.e. an "average" one, like a Conti) then that "break even" grade is even steeper. Shocking, huh? Conversely, if you're insist on running a slow clincher, that grade will be shallower, but not by much.

This is actually one of the few cases in bicycling equipment were to get faster, you actually have to add weight.

Oh yeah...please don't trot out the "rotating weight" argument. That's one dead horse that doesn't deserve to be beaten once again.

So...in summary. Tubulars rule (especially Tufos) and every tire should be pumped up to it's highest possible pressure. Carry on.

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http://bikeblather.blogspot.com/

I agree with everything you said. To really be a weight weenie the obsession with weight MUST defy logic!

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Geoffrey Nenninger

The front wheel?

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Geoffrey Nenninger

Oh crap...I think he's onto us....

Actually, perhaps a reading of this is in order:

http://www-rohan.sdsu.edu/...sa/thermo/thermo.htm

Enjoy!

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http://bikeblather.blogspot.com/

i'd like to suggest a slightly easier way to test this. its very hard to do real constant power output. if you have access to a computrainer or other device or set of devices that (a) has a power meter and (b) has a way to adjust rolling resistance by varying on-tire pressure, you can:

1) inflate tires to some defined PSI
2) install bike on device
3) engage rolling resistance with tire to the very first contact point
4) crank up rolling resistance by a defined amount (e.g. turns of the computrainer knob)
5) ride bike and perform a rolldown test
6) repeat with other tire

keep in mind warmup etc. required to make this accurate.

if the rolldown test shows less rolling resistance at the same "knob setting", then there is less rolling resistance and you will have a numeric value for the difference.

ACK!
Let's just cut to the chase real simple like-
you - tubulars have no tubes, along with some other stuff, but who cares now.
me - yes they do and they are exactly the same as clinchers

you - 2 pounds of difference between 404 clinchers with gp4000 and 404 tubulars with conti comp's.
me - just under one pound of difference for the SET.

I'm done

That weight is out on the rim. So basically double the weight for rotation (when moving).

I was responding to your "221 grams, anything else" statement. You didn't add the front wheel. I never said there was 2 pounds difference between tubular 404's and clincher 404's. I said one might save UP TO a couple of pounds with tubulars. I very clearly pointed out that the 522 gram difference I got when I looked up weights for clincher 404's vs. tubular 404's was "a little more than a pound." Who cares?

What I meant initially was that a tubulars' tube is a part of the tire. To take it out requires a high amount of effort and a blade. Because it doesn't have a clincher style tube, a tubular is not as prone to pinch flats (and I am by far not the only person to assert this, it is practically common knowledge).

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Geoffrey Nenninger

I didn't make that statement.

sorry i meant to reply to ErnieK

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Geoffrey Nenninger

"Hope that helps with your decision. I do NOT race on tubulars because I think they are faster or because I think they are better made."

screw all the works better stuff.
tubbie glue is the bomb.
It is all about the smell of glue.
Clinchers stink.
Just take a good wiff.
If bikes were logical we would never spend more than $100. for a bike.
ride what makes you feel good about the sport.
For me it's tubbies and box rims.
Cheep bikes with good wheels and tires. well not real cheep.
They bring me back to my roots in cycling and the fun I have had in the sport.

OH they are safer to.

Thom

I don't think anyone has mentioned this yet, but the beloved Tufo tubulars DO NOT have tubes. I guess you'd call them a "tubeless tubular". And just to make things even more complicated, pretty soon we'll probably start seeing more of the tubeless clinchers that Mavic, Michelin and others have been working on.

Greg.

Anyone have a cross section as to how these tubeless clinchers mount?

If they are anything like the MTB wheels out there, I'd be a bit concerned as I've witnessed many of those "burp" off wheels---sounds like a gunshot.

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