Low-aspect ratio tires: pressure gain?

It is normal for tire pressure to increase by a few PSI when driving = since the tires and the air in them heat up. That's why you're supposed = to measure it when tires are cold. However, I don't remember it being = only a low-aspect ratio tire phenomenon (by the way, what tire size are = we talking about here?). All my tires did this.

Also, you will gain about 1 extra PSI for every 10F increase in ambient = outside temperature.

Cheers,

Pete

That's more like 10%, not 0.5%.

Just a guess here - the lower-aspect tire contains a smaller volume of air, but the heat generated by friction is related to the surface area that contacts the road, which for tires of similar width should be similar. So in the lower-aspect tire, you have a smaller volume of air receiving a similar quantity of heat, thus a greater rise in temperature, thus a greater rise in pressure....?

-- Mike Smith

Thanks, Pete. My tires are the TT V6 one-grade-up tires, 225 40 aspect ratio

92Y. "Sorry, dear, they were already on the car."

It is normal for tire pressure to increase by a few PSI when driving since the tires and the air in them heat up. That's why you're supposed to measure it when tires are cold. However, I don't remember it being only a low-aspect ratio tire phenomenon (by the way, what tire size are we talking about here?). All my tires did this.

Also, you will gain about 1 extra PSI for every 10F increase in ambient outside temperature.

Cheers,

Pete

Might just be moisture in the air.

Absolutely. From autocrossing experience, I've measured on average

2-3 pound increases in sequential runs for the first couple of runs. I've had to remove up to 7-8 or eight PSI to keep the tires at 40 PSI when the pavement was hot. A four pound increase is not unusual once the tires get warm.

Elroy

2000 S4

Thanks, E!