N/A tire pressure in the car

[Spring Ford]

Here is a nice article that gets right down to what you need to know about how tire pressure varies with temperature (and water vapour in tire too). You pretty much just need to look at the picture (or the zoomed one). To understand the various water cases you will likely need to read that section.

I was surprised how little effect there is. 70F to 100F changes pressure by less that 10% even with water-saturated air.

Poor web site visually, but hey, it's free

(I shouldn't really have been surprised 'cos it's a linear effect and 70F is about 530 Rankine (Fahrenheit scale but based at absolute Zero). 570/530 = 1.08 or an 8% increase.)



https://www.mojotiretools.com/N2_FAQ_Q01.htm

 

[Mongoose Aviator]

I inflate to the door jam sticker values, never had a problem. I check all tires (and fluids, etc.) once a month and before any long trips.

If you want to know what the tires heat up to then stop an hour into the drive and check the tire pressure. Assuming no Tire Pressure Monitoring System that reports into the dash. With a TPMS then it should be blatantly obvious how the tires heat up during a drive.

When checking my cold tires, if they are within 2 lbs then I do not bother changing pressure. If one of them is off by more then 2 lbs then I set them all to the door sticker. Benefit of setting them is then at any point if one tire is significantly off then I know we have a tire issue because I previously set them all proper.

Hauling heavy loads, off-road or tires different from the door sticker than use somebody's good experience to set the tires.

 

[Ted]

I inflate to the door jam sticker values, never had a problem. I check all tires (and fluids, etc.) once a month and before any long trips.

It's amazing, it's almost like there's a reason the company chose those numbers.

Seriously, there are sometimes reasons to change vs. stock, but for 99% of drivers in 99% of cars, there isn't other than "I read on the internet that I should [do something else]." Sounds a lot like some of the advice we see in aviation.

 

[Dan Thomas]

It's amazing, it's almost like there's a reason the company chose those numbers.

Seriously, there are sometimes reasons to change vs. stock, but for 99% of drivers in 99% of cars, there isn't other than "I read on the internet that I should [do something else]." Sounds a lot like some of the advice we see in aviation.

That there. The pressure is determined by the load on the tire and per square inch of its footprint. It's the same with airplanes. If the pressure is too high, the footprint gets smaller and the center of the tread wears out faster. If the pressure gets too low, the footprint gets too large, handling suffers, and the tread edges wear out faster.

In my '07 Ranger, the sticker calls for 35 PSI all around. If I do that, the rear tires wear out in the center way too soon. so I keep them around 32 unless I'm loading it up.

These are both exaggerated to give you the idea:

 

[Pinecone]

It's amazing, it's almost like there's a reason the company chose those numbers.

Seriously, there are sometimes reasons to change vs. stock, but for 99% of drivers in 99% of cars, there isn't other than "I read on the internet that I should [do something else]." Sounds a lot like some of the advice we see in aviation.

And as I said before, the sticker pressure is a compromise between performance and comfort.

I prefer the longer tire life and better gas mileage of a slightly higher pressure.