[1stM]

I did with the manual for M package, but now I'm staying with 36F and 40R.

[Ravenseal]

Originally Posted by 1stM

I did with the manual for M package, but now I'm staying with 36F and 40R.

That's for four passengers and luggage, aka the maximum load of the vehicle.

[RockCrusher]

Originally Posted by Carefree

With the huge temperature variation during an Arizona winter I’d be adjusting pressure perhaps daily.

Rule of thumb it is.

One doesn't have to set the tire pressures daily.

Just set the tire pressures to be correct at the coldest expected temperature.

If 60F is the expected low -- even if every overnight low doesn't get that low -- set the tire pressure so it is correct (not under inflated) at 60F.

Say you check the cold tires (cold in that the car has not been driven in a sufficient amount of time) at 70F set the tire pressures 1psi higher than the desired tire pressure at 60F.

When the tires cool down to 60F the cold tire pressure would still be in spec.

Running tires under inflated is a no no. But the tires can safely tolerate pressures above the cold pressure. As the car is driven and tire pressures can climb 3, 4 or more PSI and the tires are quite ok with this increase in pressure. The hot tire pressure does not get even close to the maximum inflation pressure marked on the sidewall. (45psi IIRC.)

As an aside it is SOP for the new tires to be inflated to if not the maximum pressure to close to it when the car leaves the factory. The tires being inflated to this higher pressure prevents flat spotting.

[aerobod]

Here we can often get 30C swings of temperature in the winter from day to night, combining that with a 10C tyre heating change, 40C variation is normal. I set a baseline of 2.0 bar (29.4 PSI) for -30C, which would see the pressure rise to 2.5 bar (36.8 PSI) with the 40C temperature change.

[Carefree]

Originally Posted by RockCrusher

One doesn't have to set the tire pressures daily.

Just set the tire pressures to be correct at the coldest expected temperature.

If 60F is the expected low — even if every overnight low doesn't get that low — set the tire pressure so it is correct (not under inflated) at 60F.

Say you check the cold tires (cold in that the car has not been driven in a sufficient amount of time) at 70F set the tire pressures 1psi higher than the desired tire pressure at 60F.

When the tires cool down to 60F the cold tire pressure would still be in spec.

Running tires under inflated is a no no. But the tires can safely tolerate pressures above the cold pressure. As the car is driven and tire pressures can climb 3, 4 or more PSI and the tires are quite ok with this increase in pressure. The hot tire pressure does not get even close to the maximum inflation pressure marked on the sidewall. (45psi IIRC.)

As an aside it is SOP for the new tires to be inflated to if not the maximum pressure to close to it when the car leaves the factory. The tires being inflated to this higher pressure prevents flat spotting.

I never said pressure was set daily but temperature variance here is 28°-120°
Thank you.

[bmhewett]

Look my car, driving pleasure and sportiness

[m2not1LE]

Originally Posted by Carefree

I never said pressure was set daily but temperature variance here is 28°-120°
Thank you.

Degrees F rather than degrees C...

But that has to be annual variation. Anyone who checks their tire pressure just once/year isn't going to be running anything close to recommended pressures on average.

[Carefree]

Originally Posted by m2not1LE

Degrees F rather than degrees C...

But that has to be annual variation. Anyone who checks their tire pressure just once/year isn't going to be running anything close to recommended pressures on average.

Never said I check it annually.
Thank you.

[RockCrusher]

Originally Posted by Carefree

I never said pressure was set daily but temperature variance here is 28°-120°
Thank you.

Ok. I misread your post.