Why doesn't the pressure in truck tyre increase when a load is put on the truck?

Question

Croix de Sud - No the pressure does not increase. The tyre will bulge a bit but if you check it with a gauge the pressure is the same as before loading.

Answer 1

Who said it didn't?

Answer 2

Because it is only the shape of the tyre that changes - not the amount of air in the tyre.

Answer 3

The load.

Answer 4

The accuracy of the gauge may not be sufficient to detect any pressure increase.

What is the weight of the unloaded truck? What is the weight of the load?

if the load is not a significant  increase over the unloaded truck then the pressure would increase only very slightly even if the tyre couldn't change shape..

If the volume of the tyre stays the same then the pressure in the tyre must also be the same, the bulging you see is due to the tyre changing shape, becoming flatter at the bottom and wider to maintain the air pressure, however it almost certainly will increase slightly, but as probably not sufficient to register on a standard tyre pressure gauge.

If the volume is made less, the presssure must increase ,asssuming there is nowher for the air to go - e.g to escape through the tyre wall or the valve.

Answer 5

Because the tire, although it is a closed system, is a dynamic system.  I think it's due to the elasticity of the tire, or it's ability to bulge which does not allow the pressure to build.  Also, the molecules in the tire's ingredients are spread enough for a seepage of air molecules, on a more minute level.

Now if you put the same pressure in a steel drum and put it under the same load, you will get an increasing pressure (not to mention potentially catastrophic results).

Answer 6

the pressure does increase?