General Discussion Triathlon Talk » Tire pressure vs. rider weight Rss Feed  
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2008-04-24 12:14 PM

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Elite
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Subject: Tire pressure vs. rider weight

Just thought I'd share this pearl I recently plucked.

I've only heard anectdotal musings about tire pressure related to a rider's weight, but apparently Michelin's got a graph, so it must be true! Since they only make clinchers, the following won't apply to tubulars, and I will only speculate that it applies to all clinchers, but here ya' go:

 

http://www.michelinbicycletire.com/michelinbicycle/index.cfm?event=airpressure.view

Riding smaller than 23c, as I do, will obviously require additional pressure.



2008-04-24 12:19 PM
in reply to: #1359631

Subject: RE: Tire pressure vs. rider weight

Interesting.  So what are the consequences of riding with a different pressure than indicated on the chart?  I am around 110 pounds, and have always inflated to 100-115psi (what the chart recommends for an 180 pound rider).

 

2008-04-24 12:24 PM
in reply to: #1359631

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Subject: RE: Tire pressure vs. rider weight
sty - 2008-04-24 12:14 PM

Just thought I'd share this pearl I recently plucked.

I've only heard anectdotal musings about tire pressure related to a rider's weight, but apparently Michelin's got a graph, so it must be true! Since they only make clinchers, the following won't apply to tubulars, and I will only speculate that it applies to all clinchers, but here ya' go:

 

http://www.michelinbicycletire.com/michelinbicycle/index.cfm?event=airpressure.view

Riding smaller than 23c, as I do, will obviously require additional pressure.



Why would you say that about riding smaller than 23c the graph shows 23c and 20c as the same.
2008-04-24 12:26 PM
in reply to: #1359631

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Subject: RE: Tire pressure vs. rider weight
Zipp recommends adjusting tire pressure by rider weight as well.

Tangente Tubulars



Tangente Clinchers:




scott
2008-04-24 12:30 PM
in reply to: #1359641

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Subject: RE: Tire pressure vs. rider weight
DMW - 2008-04-24 9:19 AM

Interesting. So what are the consequences of riding with a different pressure than indicated on the chart? I am around 110 pounds, and have always inflated to 100-115psi (what the chart recommends for an 180 pound rider).



To minimize rolling resistance you want enough air in the tire that it doesn't "flatten" too much, and thus increasing the amount of tire contact to the road, but not so much air that the tire bounces as it rolls over the imperfections of the road.

So as a lighter rider riding with higher tire pressure you're tires are possibly bouncing slightly.

scott
2008-04-24 12:39 PM
in reply to: #1359641

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Elite
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Armpit of Ontario
Subject: RE: Tire pressure vs. rider weight
DMW - 2008-04-24 1:19 PM

Interesting.  So what are the consequences of riding with a different pressure than indicated on the chart?  I am around 110 pounds, and have always inflated to 100-115psi (what the chart recommends for an 180 pound rider).

The link below the graph explains deflection and links to further FAQs.

 



2008-04-24 12:46 PM
in reply to: #1359654

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Elite
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Subject: RE: Tire pressure vs. rider weight

davhamm - 2008-04-24 1:24 PM Why would you say that about riding smaller than 23c the graph shows 23c and 20c as the same.

My mistake - I meant riding smaller than 20. I ride Michelin P2R's in 20c but when I posted I was also thinking about my Continental 19's that I have mounted on my other wheelset so that's how I febuddled my post. Sorry.

2008-04-24 12:46 PM
in reply to: #1359631

Subject: RE: Tire pressure vs. rider weight
Cool.  Thanks!
2008-04-24 4:55 PM
in reply to: #1359631

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Subject: RE: Tire pressure vs. rider weight

According to the chart I should have max psi in my tires. But if I do that I'm running a risk of a blowout because of temp rise , oh what do I do!!!

 

 

2008-04-24 6:22 PM
in reply to: #1360348

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Subject: RE: Tire pressure vs. rider weight
Donto - 2008-04-24 2:55 PM

According to the chart I should have max psi in my tires. But if I do that I'm running a risk of a blowout because of temp rise , oh what do I do!!!

So funny you said that.  That's what happened to me at my last race (I'm deducing).  Inflated to 120 psi when it was 65 and it blew when it was 85.....

Here's the plan, fill them to 120, then have a temp. guage on the bike.  Every 5 degrees, stop, get off, and let air out of the tires.  If the temp drops, fill them up.  Easy!  Shouldn't hurt race times at all......

BTW - everythign should be in sarc



Edited by Aikidoman 2008-04-24 6:24 PM
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