On Sat, 2 May 2015 19:05:37 -0700 (PDT), wrote:

On Friday, April 9, 2010 at 10:34:56 AM UTC-5, LM wrote:
On Wed, 7 Apr 2010 00:52:17 +0000 (UTC), Don Klipstein wrote:

That does sound to me large for a tire, maybe about right for a tire for
a large SUV. Also, most car and SUV tires are not inflated past 36 PSI.
50 liters at 36 PSI, if compressed to 150 PSI, takes up 12 liters.

What volume of gas is contained in an automotive ti
http://www.madsci.org/posts/archives...5256.Ch.r.html

Those guys came up with 10 liters at 30psi, given:
* Inside diameter of rubber tire 15" = ~40 cm = 4 dm
* Outside diameter of rubber tire 21" = ~50 cm = 5 dm
* Width of steel wheel 6" = ~15 cm = 1.5 dm
* Pressure inside the rubber tire 30 psi
* Temperature 25° C

The volume inside the tire is the volume difference between two cylinders,
one representing the entire wheel/tire assembly and the other representing
just the wheel.

The volume of a cylinder is V = p × diameter × height where diameter is
twice the radius.

Note: For your particular tire and wheel assembly, you can use the Tire
Diameter and Circumference Calculator at:
http://www.csgnetwork.com/tiresizescalc.html

They used the numbers below:

For just the steel wheel, the volume p × (4 dm ¸ 2)2 × 1.5 dm = 19 cubic
decimeters (i.e., 19 liters).

For just the rubber tire assembly, the total volume p × (5 dm ¸ 2)2 × 1.5
dm = 29 cubic decimeters (i.e., 29 liters).

The volume difference is just 10 liters (which means that the air in the
tire will mass about 26 grams).

Another volume calculation is he
http://www.irday.com/html/Automotive...0413/9827.html
Those guys came up with 30 liters for an average truck tire.

This volume calculation puts a car tire at 1 to 2 cubic feet of air:
http://mgaguru.com/mgtech/tools/ar104.htm

BTW, what happens to the mass if we use a different gas than air, like
carbon dioxide?

Many people are using nitrogen in their tires now and paying a premium for it. The benefits are not so from the physical qualities of the gas, but the fact that the gas contains absolutely no water. So the tire pressure changes less due to temperature changes.

Some of the benefits most certainly are from the physical properties
of the gas. Aside from the benefits due simply to lack of water
vapor, the hydrogen migrates less thru the tire structure and that
makes the tire pressure stay up longer then when you use plain old
air. In addition, the nitrogen does not oxidize the tire materials
the way the oxygen in plain old air does and that also is beneficial
to tire life. All that said, for most people the benefits of nitrogen
are relatively small and if you pay much for it you may not recover
that extra cost. For truckers the benefits are much
greater,particularly the benefits of the tire components not being
oxidized since they will retread a truck tire many times over it's
carcass life. And with nitrogen the carcass will last longer.