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Tire Pressure

Old 10-15-07, 09:19 PM
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Tire Pressure

I run 120 in my ProRace2's.

Iíve recently had other racers tell me they use 140. Iím interested... by am leery of cornering at 140.

What about keeping 120 in front, and cranking up the rear?

What do you peeps do?
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Old 10-15-07, 09:40 PM
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115, pro2 race's I've never seen a ProRace2.

[/petpeeve]
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Old 10-15-07, 09:54 PM
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Here we go again. The side of the tire says to inflate to a max of 116 psi. Some say that much over that and you run the risk of blowing the tire off the rim while racing. Others say that is a bunch of lawyerly crap and you can go well above that. Still others say that more psi creates a less efficient tire. I'm with NomadVW (and Sheldon Harris) on this one. I run 115 in the rear and 110 in the front. I weigh 172.
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Old 10-15-07, 10:55 PM
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100 front and back. I'm 136 lbs.
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Old 10-15-07, 11:45 PM
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Yay!!!

Another tyre pressure thread!!!
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Old 10-16-07, 04:58 AM
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135 front and back. no problems
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Old 10-16-07, 05:05 AM
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110 front, 115 back, i weigh ~171 #
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Old 10-16-07, 07:59 AM
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116-7 front / 120 rear and weigh 150. Pro2 Races, BTW
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Old 10-16-07, 08:09 AM
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Originally Posted by daytonian
135 front and back. no problems
What do you weigh?
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Old 10-16-07, 08:51 AM
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150 PSI


*post to piss off the "less PSI crowd"*
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Old 10-16-07, 09:16 AM
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It really depends on your weight and the road conditions you're riding on.
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Old 10-16-07, 09:23 AM
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Originally Posted by Speedee
I run 120 in my ProRace2's.

Iíve recently had other racers tell me they use 140. Iím interested... by am leery of cornering at 140.

What about keeping 120 in front, and cranking up the rear?

What do you peeps do?
I bet your rims aren't rated for that much pressure.

110-115 front, 115-120 rear @ 250
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Old 10-16-07, 09:25 AM
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There's a nice little chart on the side of the PRace2 box that has a weight/inflation graph, that's what I go by. I'M hoping the tire people know more then I do.
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Old 10-16-07, 09:34 AM
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General wisdom.

1. The lower the tire pressure, the more grip you will have, the higher the pressure, the less grip. (I'm not even going to touch the issue of rolling resistance)

2. The rear tire carries much more weight than the front tire does, so it should run at a higher PSI than the front.

I run the front at about 85-95 for max grip on the front, because a slip of the front will almost always result in a fall. A rear slip, however, is very easy to catch. Thats why I run about 120 on the rear so that hopefully the rear will slide before the front does.
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Old 10-16-07, 10:04 AM
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We have a lot of rough chipseal, which will slow you down a lot at higher pressure. I run 110 rear, 100 front, and I weigh 178 lbs. I let the pressure bleed down to 95/85 or so during the week, then reinflate.
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Old 10-16-07, 10:35 AM
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Originally Posted by Speedee
What do you weigh?
170 lbs
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Old 10-16-07, 10:39 AM
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Originally Posted by waterrockets
We have a lot of rough chipseal, which will slow you down a lot at higher pressure. I run 110 rear, 100 front, and I weigh 178 lbs. I let the pressure bleed down to 95/85 or so during the week, then reinflate.
You don't get pinch flats at 85?
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Old 10-16-07, 12:47 PM
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Originally Posted by prschaa
There's a nice little chart on the side of the PRace2 box that has a weight/inflation graph, that's what I go by. I'M hoping the tire people know more then I do.
From the Michelin web site for Pro2 Race I found this image, is this it? It appears to be generic to all of their tires:


According to the chart, everyone 80 kg (176 lbs) and up should be inflating to 8 BAR (116 PSI).

I'm doing 120 front and back at 175 lbs, which appears to be about right.
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Old 10-16-07, 12:59 PM
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Originally Posted by daytonian
You don't get pinch flats at 85?
Naw. I pump up for rides and races where I might not so easily see bumps. That 85psi is on the front. The rear just gets into the upper 90s.
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Old 10-16-07, 01:13 PM
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you guys must have some really great pumps to inflate your tires to such exacting psi's
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Old 10-16-07, 02:12 PM
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Yeah, with a decent pump, it's pretty easy on the last stroke to push down until the pump's valve pops open, then just do a partial stroke until you reach your target pressure.

Most of the time, I'm +/-2 psi or so. It doesn't matter.
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Old 10-17-07, 11:52 AM
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I pump mine up and gauge it old school.... I Tap the side wall with my index finger until you can hear the tube wanting to burst out the side wall.....(my Gauge is broken on my Silca Pump Circa 1991)
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Old 10-17-07, 08:51 PM
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I learned the hard way that if you overinflate a tire you can roll it off the rim in a crit. unlike a normal flat,
the deflate immediately. Was very fortunate not to go down and take others with me, but cracked an aluminum rim.
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Old 10-17-07, 11:58 PM
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Funny timing of this. I usually go 100 front, 100-110 in the rear with my PR2. I weigh 147lbs. I got a flat in the front, and put in the C02 cartridge. It started to rain, and the ride felt noticeably awesome. It was even noisy, which I like, but it had better feel. Anyhow, got home and checked the pressure, it was about 80. I think tomorrow, I am going to try 90 & 100 and see how that feels.
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Old 10-18-07, 06:29 AM
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Originally Posted by pelikan
Funny timing of this. I usually go 100 front, 100-110 in the rear with my PR2. I weigh 147lbs. I got a flat in the front, and put in the C02 cartridge. It started to rain, and the ride felt noticeably awesome. It was even noisy, which I like, but it had better feel. Anyhow, got home and checked the pressure, it was about 80. I think tomorrow, I am going to try 90 & 100 and see how that feels.
I was pre-riding a TT course with a friend, and there was this 4-mile section with horrible chip-seal. He was getting beat to death, and really falling off the pace. I convinced him to drop his tire pressure and he got a LOT faster. When we got back to the car, he was at 100psi in the rear, and he weighs 205.

I think a lot of people over-inflate for the road conditions. On a rough chip seal road, the higher pressure will really slow you down, aside from the discomfort. It amounts to constantly climbing and descending little 1.5mm hills.
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