Rolling resistance of tubulars vs clinchers

Discussion in 'Cycling Equipment' started by park, Mar 22, 2006.

  1. park

    park New Member

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    I have a friend who is selling his tubular rear disk/front 404 for a clincher version of the same. He is convinced that clinchers have superior rolling resistance based on a study he found. He thinks he might see a 1-2 min difference in a 40k.
    Can anyone confirm this? Don't the pros use tubulars on their time trial bikes?
     
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  2. free_rideman

    free_rideman New Member

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    That wouldn't make any sense, since tubulars are meant to run much higher perssure than a normal clincher. But hey, who knows, I never used a tubular tire. One thing that I do know is that tubulars have a much more rounder profile. That could be the reason, but maybe that gets offset by the high pressure? Thus making it the same, but improving cornering traction?

    -yeah but pros do run them, like the overated Lance Armstrong
     
  3. DiabloScott

    DiabloScott New Member

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    Yes the best clinchers have less rolling resistance than the best tubulars.

    Here's the perfect link and it shows as much as 4 minutes difference (clinchers faster) over 40km depending on what factors you input:
    http://www.analyticcycling.com/ForcesTires_Page.html
     
  4. park

    park New Member

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    I saw Johan Bruynel get excited about shaving seconds off Lance's times because of dimpled fabric in his skinsuit. We are talking about shaving off minutes which is huge! Why then do the pros use tubulars if clinchers would allow for that much time gain?
     
  5. Insight Driver

    Insight Driver New Member

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    I do believe one study (Jobst Brandt's) does not prove clinchers are faster in road races. Mr Brandt's study did not state on which surface the tires were run, nor the methodology of the testing. There are other studies that, on typical road surfaces (which can be rough, or even cobblestone) tublars have slightly lower rolling resistance than clinchers. Anecdotally, time trialists in road races like the Tour De France use tublars. On a track, that's a whole different story because the surface is very smooth.

    Don't take anything as bible. Many people carry an opinion and look for data that proves it. A fool is born every day. Believe none of what you hear and only half of what you see. Your mileage may vary.
     
  6. DiabloScott

    DiabloScott New Member

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    There are a lot more studies than just Jobst's that show rolling resistance favors clinchers. And there are other reasons for preferring tubulars that have nothing to do with RR. And the numbers I used in the calculator were for a totally flat course where tubular weight advantages would be minimized.

    The idea that rolling resistance of tires on cobbled streets is any kind of factor at all makes me chuckle. Chip seal yes and I like the way sewups feel on that kind of surface but I don't know if it has any effect on RR.
     
  7. TWOPBikeGuy

    TWOPBikeGuy New Member

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    I dont know much about tubulars, but I do know that my Fortezza Clinchers run up to 175 psi, pretty high, I would think higher than most Tubulars. I do know that the higher pressure you run the better chance of avoiding hydroplaining, which is why I think Airplane tires run at 300+ psi.
     
  8. DiabloScott

    DiabloScott New Member

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    Bicycle tires are not wide enough to hydroplane - even the really big MTB slicks... it can't happen (don't confuse hydroplaning with slipping on wet corners). Also, rolling resistance doesn't automatically go down with higher tire pressure - the relationship is more complex than that.
     
  9. alienator

    alienator Well-Known Member

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    First rolling resistance isn't linear with tire pressure. Rolling resistance does go down w/ increasing pressure.....to a point. After that point, rolling resistance increases.

    Also for a bike to generate enough wedge pressure in water to hydroplane, it has to be going about 100mph.

    Airplane tires run at a high inflation pressure because they've got a huge amount of weight to hold up. It has nothing to do with rolling resistance.
     
  10. JohnO

    JohnO New Member

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    According to the article, Brandt's study was done with a metal cylinder spinning the wheel. The overall picture is more complex than that - rider weight, wheel weight, prevailing wind, etc...

    Back to the original topic, swapping Zipp 404/909 tubies for clinchers... the buyer should be aware that the clincher rims weigh a bit more, adding to spinning weight, due to the aluminum rim that must be fitted to the carbon wheel. That will also have an impact on performance. It's never a simple answer.

    I bought a used set of 404's in tubie, and just love them. Hard to take them off the bike. Smooth ride, and ever so fast on the downhills.

    Yes, clinchers are easier to repair, but curiously enough, the last two flats I had with clinchers were sizeable cuts, rendering the casing useless. Didn't matter that I could change the inner tube easily, the result couldn't be ridden. Sure wish I'd had a tubie tucked under the seat on those days...
     
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