Why do road bikes coast better than other bikes?
07-04-20, 10:39 AM
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True. I'm a fat guy with good hubs. I pass a lot of skinny people on downhills.
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07-04-20, 10:42 AM
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Hub drag is nearly irrelevant in real life. At any speed over 12mph, air drag is the dominant force ******ing the cyclist. The lower air drag of a 23mm tire vs a 32mm or more section clincher is real. The better aero position of being on the drops, even on the hoods vs. being sat upright ... ...
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07-04-20, 11:03 AM
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07-04-20, 10:40 PM
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This thread reminds me of an old tale:
Who’s going faster? The fat guy at 20mph or the skinny guy at 20mph?
Who’s going faster? The fat guy at 20mph or the skinny guy at 20mph?
07-06-20, 10:23 AM
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I can verify this with an experiment I did:
Run 1: Recumbent bike, pedal to about 48 mph, then coast down. Top speed achieved: 54 mph, sustained for about 10-12 seconds.
Run 2: CBR66RR sportbike (~400 lbs) start run at top of the hill ~50 mph, pull in clutch and coast. Top speed achieved: also 54 mph sustained almost the same time.
Run 3: Strada Carbon Velomobile (~80 lbs) pedal to about 48 mph. Top speed: 68 mph, sustained for about 8-10 seconds. Coasted MUCH further even after it started to flatten out than the others.
07-06-20, 03:37 PM
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They dont always. My son and I went for a ride a couple days ago. He rode his skinny wheeled racing bike. I was riding my RANS Stratus LE. Every time we coasted down hill I would easily out coast him.
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07-07-20, 02:55 PM
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Lower rolling resistance from more supple slick tires and better aerodynamics.
Down hill sectional density of the rider is significant. Heavier ones are faster.
Down hill sectional density of the rider is significant. Heavier ones are faster.
07-07-20, 03:39 PM
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- the very heavy, very skinny guys usually win @ downhill.
07-07-20, 10:32 PM
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Downhill terminal velocity in a freewheeling descent will be roughly proportional to the square root of M/A, the ratio of combined mass over combined frontal area of cyclist and rider. That generally favors larger cyclists.
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07-08-20, 03:19 PM
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In actual test a couple of surprising results came out . A wider supple tire out coasted a narrow hard tire. A 20" tire out coasted and 26" tire.
07-08-20, 03:52 PM
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