Temps vs Pressures

[toocrazy2yoo]

So, I run my tires at around 32f/30r, give or take. Higher pressures are a little more efficient but pretty had on the suspension, so I keep em to spec. First night the temps dropped to 12 or so, I had a TPMS light for a low tire. I checked them, they were around 24psi, but it was a little warmer by then. I took em up to 34 all the way around when it went up to around 55, and now, in Florida, it's 80 daytime, 60 or so nights. This back and forth between various climates is a pain, but I was wondering if there a table or graph that shows pressure differentials for a given pressure/temp change? Is such a thing possible given the variety of tires, or are these things simple physics? Sure as I'm sitting here, soon as I head back North, pressures will drop again. Would be nice to be overfilled a little going up, so that they fall into a happy balance later and I won't need to fool with it up there. Any clues?

 

[XS650]

Absolute tire pressure is directly proportional to absolute temperature.

For tires in the low 30 psi range, the pressure changes about 1 psi for each 10 deg F temperature change of the air inside the tire.

 

[Nyquist]

If you knew the volume of your tires, you could use the Ideal Gas Law or Van der Waals Equation to calculate what your tires' pressures would be at any given operating temperature.

 

[XS650]

Originally Posted By: Nyquist
If you knew the volume of your tires, you could use the Ideal Gas Law or Van der Waals Equation to calculate what your tires' pressures would be at any given operating temperature.


You would need more information.

 

[Boomer]

Ideal gas law P1V1=nRT1 So P1V1/T1 = nR, a "constant".

Assuming the volume of the tire is not changing appreciably, then P1/T1 = P2/T2 Use absolute temperature in K or (oC + 273) and do the math.

 

[Eddie]

I set my after sitting overnight. I use a digital gauge and set 2 psig over door recomendation.

 

[jorton]

Originally Posted By: Eddie
I set my after sitting overnight.


very good plan for cars that handle like a go-cart.

Originally Posted By: Eddie
set 2 psig over door recomendation.


very good plan for cars that handle like a boat.

 

[SrDriver]

Here is some information on tire pressure.

Link To Web Site