Did I miss where you addressed the weight argument against clinchers? Aren't tubulars significantly lighter?
Depends on what you think is "significant", I guess. A reasonable clincher tyre for every-day use is about 300 grams including the inner tube.
A race tire/tube might be lighter, but say 250 and you get all but the very lightest around.
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A comparable tubular tyre might be lighter than that, but not by much.
You can get about 30-50 grams lighter at the same level of durability. But at these weights neither the clincher nor the tubie would be all that durable.
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The tubular rim is also lighter, but the weight different is something like 20 grams per rim.
Well, rim weight can be more significant than that. We used to use rims that were on the order of 200-250g, some even under 200g. Clinchers just can't be that light. Maybe as much as 100g difference per wheel. Also, modern rear wheels, with the extreme dish, need a heavier rim, so you would not save that much in the rear.
All told, you could approach 150-200g lighter using tubulars. As to whether or not that is significant, it obviously depends on what your team is willing to put out for you. If you are not with a team, I don't see the point of the discussion, since the economics alone clearly favor clinchers, not to mention the hassle factors.
The UCI sets the minimum bicycle mass at 6.8 kg, so if that figure can be reached through weight savings elsewhere, the heavier clincher rim/tire combination would not be a disadvantage to a professional racer.
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And pro racers generally have full mechanical support. When was the last time you saw a pro fixing a flat or changing a tire in the middle of a race? The support car comes to their aid with a whole new wheel, and away they go. So for all we know, their tires could be glued on permanently with 3M 5200 or something.
If I remember correctly, the world famous bicycle designer Mike Burrows writes in his book "Bicycle Design: Towards the Perfect Machine" that the only sensible reason to use tubulars is in TTs, where a quick tyre change could "keep you in the money" - there being a small financial reward for a placing. I believe support vehicles are uncommon in British TTs.
I can't possibly believe tubulars are such a bad idea. Wasn't the Paris-Roubaix won on them again this year? That's a race where the pros ride all sorts of non-standard equipment, from cross-bikes to front suspension, special wheels etc. Time and again many choose tubulars.
We are all going to be riding tubless clinchers soon anyway.....
Plugging in a few reasonable numbers (5000 watts, 280 g rim) produces a rim temperature rise of about 20 C/second. Ignoring cooling, it would take less than 4 seconds to raise the rim temperature to 100C, presumably well above the glue melting temperature.
Nice analysis. I don't know anything about tubular glues, but many adhesives melt at temperatures well above 100C. So to pick a nit, I think it would take a bit more than 4 seconds.
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Terry Morse said:
Plugging in a few reasonable numbers (5000 watts, 280 g rim) produces a rim temperature rise of about 20 C/second. Ignoring cooling, it would take less than 4 seconds to raise the rim temperature to 100C, presumably well above the glue melting temperature.
Nice analysis. I don't know anything about tubular glues, but many adhesives melt at temperatures well above 100C. So to pick a nit, I think it would take a bit more than 4 seconds.
You don't need the glue to melt, ie convert to a liquid, for there to be a problem.
You only need it to soften enough to creep. That can be a long way before the melting temperature is reached.
Nitpicks need to be nitpick proof themselves, otherwise they make one look like a nit. -- Mark South Citizen of the World, Denizen of the Net <<Tiens! Ce poulet a une grenade!
We are all going to be riding tubless clinchers soon anyway.....
I thought we were going to be riding "Tubiesto clinchers."
-a
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I can't possibly believe tubulars are such a bad idea. Wasn't the Paris-Roubaix won on them again this year? That's a race where the pros ride all sorts of non- standard equipment, from cross-bikes to front suspension, special wheels etc. Time and again many choose tubulars.
They choose wacky dietary supplements, astrology, and weird pre-race rituals too.
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We are all going to be riding tubless clinchers soon anyway.....
Many tubular rims are lighter than similar clincher rims, and in the past this was almost universally true.
But I've recently heard that Ksyriums, for example, have clincher and tubular rims of the same weight. The tubs apparently have extra metal in the edges for denting resistance. Can anyone measure this?
I don't see a conflict with your RR data and preferring tubies; because it seems that tubies can be pumped up to a far ( an additional 20-40 lbs?) higher tire pressure than clinchers while maintaining the same comfort, therefore _more_ than overcoming the glue factor.
Gosh, a clincher at 130-140- now THAT's real punishment!
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I don't see a conflict with your RR data and preferring tubies; because it seems that tubies can be pumped up to a far ( an additional
20-40 lbs?)
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higher tire pressure than clinchers while maintaining the same comfort, therefore _more_ than overcoming the glue factor.
What is your source?
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Gosh, a clincher at 130-140- now THAT's real punishment!
Actually the comfort benefit is derived from the ability to run *lower* pressures without risk of pinch flats. Running 95 psi is not uncommon with sewups for long continental pro races. I have no idea where this trend of running super high pressure came from except perhaps people have been over- reacting when they got an occasional pinch flat on their clinchers tires.
