How can wider-lower psi tires REALLY be that fast?
03-13-11, 07:54 PM
#101
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Uh, no. And it hasn't been for several DECADES. There are those who treat it (and other rando rides) as a race, but that's their problem. There are no prizes, no formal standings, and no special recognition for being faster that everyone else, except for bragging rights - and the only people who care about those are the (maybe) 10% of the riders who "race" the events. Yes, I am impressed by those who finish brevets far faster than I could. But did they "beat" me? Not in my book.
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03-13-11, 07:57 PM
#102
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Small diameter tires have a higher rolling resistance at the same tire pressure, because tire deformation is proportionally more important, in other words the tire is "less round". Wider tires roll better than narrow ones. This assertion generally generates skepticism, nevertheless at the same tire pressure a narrow tire deflects more and so deforms more.
Why do wide tires roll better than narrow ones?
The answer to this question lies in tire deflection. Each tire is flattened a little under load. This creates a flat contact area. At the same tire pressure, a wide and a narrow tire have the same contact area. A wide tire is flattened over its width whereas a narrow tire has a slimmer but longer contact area. The flattened area can be considered as a counterweight to tire rotation. Because of the longer flattened area of the narrow tire, the wheel loses more of its "roundness" and produces more deformation during rotation. However, in the wide tire, the radial length of the flattened area is shorter, making the tire "rounder" and so it rolls better.
The answer to this question lies in tire deflection. Each tire is flattened a little under load. This creates a flat contact area. At the same tire pressure, a wide and a narrow tire have the same contact area. A wide tire is flattened over its width whereas a narrow tire has a slimmer but longer contact area. The flattened area can be considered as a counterweight to tire rotation. Because of the longer flattened area of the narrow tire, the wheel loses more of its "roundness" and produces more deformation during rotation. However, in the wide tire, the radial length of the flattened area is shorter, making the tire "rounder" and so it rolls better.
03-13-11, 08:00 PM
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03-13-11, 08:09 PM
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Originally Posted by bobbycorno
Uh, no.
03-13-11, 08:11 PM
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When did I say that weight DOESN'T matter to racers? I raced for 15 years - I'm very familiar with how important rotating weight is in that scenario. But for those of us who don't race, weight is a FAR overrated factor. My issue is with those who assume that since racers use something, it's the best for EVERY purpose.
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Don't.
03-13-11, 08:34 PM
#106
No one cares
When did I say that weight DOESN'T matter to racers? I raced for 15 years - I'm very familiar with how important rotating weight is in that scenario. But for those of us who don't race, weight is a FAR overrated factor. My issue is with those who assume that since racers use something, it's the best for EVERY purpose.
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Jack Taylor Super Tourer Tandem (FOR SALE), Jack Taylor Tour of Britain, Px-10, Carlton Flyer, Fuji The Finest, Salsa Fargo, Santa Cruz Tallboy, Carver All-Road .
03-13-11, 11:50 PM
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Low pressure, tires with thick rubber treads will suck the life out of your legs in no time flat. So, yes, rolling resistance is important even to non-racers.
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