Tire pressures during temperature swings

donn0128 wrote:
I checked my tires at the start of the season and left them alone.

If that means that you don't check the pressures again during the season, you are playing with fire and it will burn your butt eventually.

So no problems if I set the cold pressure at 15F ambient and later in the day it's 50F ambient? Often see huge swings like that around spring.

This is all silly nonsense. Unless you have a leak a tire will only loose 1-2 pounds in six months. I checked my tires at the start of the season and leave them alone. Heck, you can loose 2 PSI every time you check them.

phillyg wrote:
According to every tire mfgrs. info, you set pressure when the tires are cold, i.e., not having been driven on, and leave it alone.

What he said^^^^^^

Tires are engineered to be driven on without constant air pressure adjustments. Set the cold pressure, hit the road, don't worry about it.

I like the statement, "don't overthink it".

And, I'd expect the pressures the next day to be nearly what they were the day before.

I've seen 8-10+ PSI increases from the coldest starts to the hottest running, and I have to admit (despite the references to tire mfg-ers statements) that it concerned me.

One time, I stopped on the side of the highway and bled 4 PSI of pressure.

I set mine at 122 in the morning and usually see temps in the 145-150 range but once going from high altitude and cold temps to lower and hot temps tires went from 122 to 165 according to TPMS.

I never bleed air from morning start, while driving to destination. I will wait until next morning, at new location, to adjust.

Yes, a 70 degree difference in temp will make a noticeable difference. While this is not the norm, in this case I might consider starting pressure a lb or two less, while days end will likely be over pressure. In any case, tires are designed to inflate when heated, but tire makers still say "go by cold pressure, before travel."

Jerry

Interesting subject. I had my TPS come on, on my car the other day. I know none of my tires leak and I usually check and air them every 3 months but it's been cold here and my tire pressure had dropped below the TPS threshold. I aired them back up and all is good.

I don't believe 3-4 pounds means squat. I always run my TP at the maximum sidewall rated pressure. I get better fuel mileage that way.

According to every tire mfgrs. info, you set pressure when the tires are cold, i.e., not having been driven on, and leave it alone.

Don't overthink the whole thing. Check your tires in the morning, adjust as necessary. Do the same the next morning, and the morning after that. Trying to keep tires at a mean pressure while actually rolling down the road is just a waste of time and effort. 10 psi pressure changes as tires heat up and cool down is perfectly normal.