Best tire pressure for best rolling resistance
04-08-14, 01:28 AM
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04-09-14, 09:18 AM
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I followed the recommendation of an online tire pressure calculator for a group ride last night. It said run 70 and 108 psi front and rear on 23c tires. I usually run 120 on both. It was SLOW.
04-09-14, 09:19 AM
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Did you estimate Crr and CdA using the Chung virtual elevation model or are you just guessing?
04-09-14, 09:34 AM
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Rock hard tires feel fast, but what makes them feel fast is actually taking energy away from going forward.
Admittedly 70psi front sounds awfully low, and likely was slower. But 108psi could be faster than 120psi depending on a range of factors.
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04-09-14, 10:25 AM
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Data? Or did it just feel slow?
Rock hard tires feel fast, but what makes them feel fast is actually taking energy away from going forward.
Admittedly 70psi front sounds awfully low, and likely was slower. But 108psi could be faster than 120psi depending on a range of factors.
Rock hard tires feel fast, but what makes them feel fast is actually taking energy away from going forward.
Admittedly 70psi front sounds awfully low, and likely was slower. But 108psi could be faster than 120psi depending on a range of factors.
04-09-14, 12:28 PM
#32
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There's a chart for this floating around the forum somewhere, but I'm too lazy to find it and it's nice outside and I want to go for a ride instead.
04-09-14, 12:54 PM
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04-09-14, 01:32 PM
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The tire pressure nerd in me made me dig this up....
https://www.bikequarterly.com/images/TireDrop.pdf
https://www.bikequarterly.com/images/TireDrop.pdf
04-09-14, 01:38 PM
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The tire pressure nerd in me made me dig this up....
https://www.bikequarterly.com/images/TireDrop.pdf
https://www.bikequarterly.com/images/TireDrop.pdf
04-09-14, 01:46 PM
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04-09-14, 01:54 PM
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Find a shallow half mile hill, surrounded by trees to buffer any wind, roll down a hundred times, changing the tire pressure up and down by 5 lbs, in a range of maybe 75 - 120 lbs (that will give 10 data points per) and get back to us with the data. Actually, that would be really interesting to see the results.
04-09-14, 02:23 PM
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I can tell the difference in 100 vs. 120 PSI, and 120 rolls better. I refuse to believe the magical rolling resistance pressure is somewhere between 100 and 120.
There may be a point at which a tire can be too hard, but 120 PSI is not it.
Pump. Them. Up.
There may be a point at which a tire can be too hard, but 120 PSI is not it.
Pump. Them. Up.
04-09-14, 03:08 PM
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04-09-14, 03:41 PM
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I went almost 2 weeks without pumping my tires, and they dropped to 70 or 80psi in the front and back. My ride was about 7% slower that day. I can't tell if it was totally due to the tires, but I assume part of it was.
04-09-14, 05:25 PM
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04-10-14, 05:32 AM
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How much do you weigh? I weigh about 160 or so, i do 100psi in the front, 110psi in the back. I may go higher now.
I went almost 2 weeks without pumping my tires, and they dropped to 70 or 80psi in the front and back. My ride was about 7% slower that day. I can't tell if it was totally due to the tires, but I assume part of it was.
I went almost 2 weeks without pumping my tires, and they dropped to 70 or 80psi in the front and back. My ride was about 7% slower that day. I can't tell if it was totally due to the tires, but I assume part of it was.
For lighter guys, it's less of an issue certainly, and common sense says the front tire is less important than the rear.
04-10-14, 09:52 AM
#45
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Continental released this rolling resistance data when they came out with the GP 4000S II. No information about what type of surface it was tested on:
I've not seen data anywhere that shows an increase in rolling resistance as tire pressure increases. This data also ignores wind resistance, weight, final gearing, pnuematic trail, and other factors affected by tire size.
I've not seen data anywhere that shows an increase in rolling resistance as tire pressure increases. This data also ignores wind resistance, weight, final gearing, pnuematic trail, and other factors affected by tire size.
Last edited by nhluhr; 04-10-14 at 11:39 AM.
04-10-14, 11:24 AM
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04-10-14, 01:27 PM
#48
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********** I think your plot just showed that. In case you meant increase in Crr with pressure, What's in a tube? - Slowtwitch.com
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