[CR]Why tire pressure doesn't go up when you set down

(Example: Production Builders:Teledyne)

Date: Mon, 5 May 2008 17:48:26 -0700 (PDT)
From: "brad stockwell" <brdstockwell@yahoo.com>
To: Classic Rendezvous <classicrendezvous@bikelist.org>
In-Reply-To: <cd45da8c0805051636q7c18e664hbaa9675eee6b86d1@mail.gmail.com>
Subject: [CR]Why tire pressure doesn't go up when you set down

Regarding Don's query below:

Wheels have an outer diameter of about 680mm which is close to 26.8". The circumference is about 84". If the width of the tire casing from bead to bead is about 2.5", then the total pressurized area of the tire is about 210 square inches. If the guage pressure is 100 lb per square inch, then the actual pressure including atmosphere is about 115 lb / sq inch. Then the total force on the tire casing is 210 in2 X 115 lb/in2 = 24,150 lb.

If you were to increase this total force by a body weight of 260lb, the difference would be... not very much.

And each tire only has to support half of that.

Brad Stockwell Palo Alto, California

Don Williams <donwilliamsjr@gmail.com> wrote: But it is...

Hi All...

I have, in the last few years, grown to a "very stout" 260 lbs. Hopefully cycling will relieve this in a reasonable time frame. But I digress...

I'm riding Continental Giros tubular tires at around 95-100 psi. As I ride them, they don't >seem< soft to me.

Confounded and looking for another data point, I sat on the bike and had my wife check the tire pressure and it really didn't seem go up... This info did not help!

As far as I know I do not live outside the jurisdictional boundary for the laws of gravity or thermodynamics...

Any one have a idea where I'm going wrong?

All I wanted to do was determine if I'll be able to ride on a pair of Veloflex Criteriums... Without blowing them to smythereens...

Don Williams Woodinville Washington USA _______________________________________________

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