tire pressure and offset

[wigner]

04 4.4i sportpack's tire pressure need to be 32 psi for fronts and 39psi for rears. but what does these pressure conditions apply for? completely cold condition or during driving? I found that the pressure increase upto 3~4 psi for each tires. so if I set it 32 and 39, 1 ~ 2 hours highway drive makes 35 and 43. what is the condition for 32 and 39?

and I found left and right has 1psi offest. say 32, 31 for fronts and 37 and 38 for rear. Is it Ok?

[motordavid]

There are pages of opins on the topic of tire pressure...
The door jamb gives rec'ds for light/std load and heavy load;
good starting point for everyday use, imo.

Yes, tire psi increases as tires warm up: tire flex, friction from
road, rolling circumference motion...makes all the lil' air molecules
vibrate, bump into each other, and that volume of molecules
occupies more "space"; thus, the pressure in the enclosed tire
increases.

Set your tires "cold", meaning not having driven on them for hours...
set them evenly as possible across the same axle. Check them
every couple of weeks, esp. after a cold snap.

39 rear is probably on the high side for a one passenger load...
These cars aren't running races or NASCAR rides.
GL, mD

[wigner]

what is the best pressure for fronts and rear? this car is for kids' preschool commute. so always two badies with carseats in the rear and my wife is driving. so what pressure should be for both of front and rear when the car is completely cold, say in the morning without driving at all.

[dkl]

39psi on the rear is really for maximum payload...meaning 4-5 adults with luggage. For lighter loads, I don't think 39psi is necessary. You'll need to experiment a bit to find the sweet spot as you'll notice tire wear patterns if you over or under inflate (tires tends to wear more in the middle when over inflate and more on the sides when under inflate). I would suggest starting with 34-35psi in the rear and go from there.

[wigner]

great thanks. but when does the 35 psi read? cold or after driving?

and what about fronts?

[motordavid]

Originally Posted by wigner

what is the best pressure for fronts and rear? this car is for kids' preschool commute. so always two badies with carseats in the rear and my wife is driving. so what pressure should be for both of front and rear when the car is completely cold, say in the morning without driving at all.

Per page 135 your manual, or the manual pdf pasted on this Board,
or the sticker on your door jamb:
32 f/ 32 r, and 32f/ 39r, when loaded to the gunnels.

That 32/32 is cold, as in the morning after sitting...this isn't
that complicated.

[dkl]

Originally Posted by wigner

great thanks. but when does the 35 psi read? cold or after driving?

and what about fronts?

Always cold reading as motordavid have indicated.

Fronts are always at approx. 32psi as various loads won't have much affect on them.

[wigner]

the same story for run flat tires?

[JCL]

Originally Posted by wigner

the same story for run flat tires?

What same story?

Always set them cold; yes, that is the same story.

The owner's manual and door jamb recommendations won't help you much if you have installed different tires than the vehicle was originally supplied with, ie run flat tires, but they are a starting point.

Back to the original question, set them to 32 all round for the conditions you describe.

[wigner]

Thanks all