stymie222

Just took a trip to Florida. I left Alabama with temps about freezing. All four Goodyear "run flats" (original equipment replacements) were at 34 PSI.
Running 70-75 mph for many hours on the Interstate, with 80 degree temps in Florida, set off the "high air pressure alert", about 40 psi.
I let out enough air to bring them all back to 34 psi.
On the way back to a cold Alabama, the pressure started to drop below what my local tire dealer recommended @ 34 psi, to 30 psi.

I don't mind the attention but wonder if short stays and short driving times in different temps warrant the effort ?

Thanks

EVRose

30 psi cold is recommended around here.

AORoads

with Eric, evrose, above. However, you can adjust the initial pressures a little up, or down, but that's after you have your own lessons learned for your car, your tires and your driving circumstances. For instance, why do you start with 34 psi when the car calls for 30 cold?

To answer the question of adjusting, yes, it can be beneficial but probably excessive for short stints in different air temps.* But not for long jaunts or stays in different areas with different temps.

Maybe the better question is to ask your local tire dealer why he recommends an air pressure in direct opposition to the placard on your door post, i.e., what does he know that the people who designed, built and specified the tires and pressures on the car don't know?

* If you take pressure readings in your garage which is say, 50 degrees in the morning, go to work and leave the car outside when the temp rises to 80. At 4 or 5 pm, assuming the car has sat all day, your car could easily read 3-4 or more pounds more than what you started with in the garage at home. Pressures tend to go up or down about 1 lb. per 10 degrees change in air temps.

jrose7004

HBsurfer

Every car has a yellow and white sticker on the drivers side door jamb that give the cold tire pressure requirements for that car. Some cars have a different pressure for front and rear tires. Don't use the pressure noted on the tire.

cclive

The tires started out about 4 psi high (34) and then with the outside temperature increase as well as the increase from running at highway speeds, the high limit was reached and the system notified you. This kind of thing can happen when there are big changes in conditions, but it is a fairly unusual situation. The 34 was a bit high to begin with as 30 is what Chevy advises and even if you went up a bit from there, 32 would be about it.
I have a similar situation where I am. In the summer, if I start out cold at 30, then I go up the mountain to a party, elevation over 10,000 ft, and I stay until late in the evening, the combination of the temp in the 30's and the change in elevation of 4,000 feet will cause me to get at least one low pressure warning. The next day in the morning, the pressure will be right on the recommended 30 psi. I don't worry about the low warning because it's only a few miles until I get down the hill a bit and the warning goes off, but if I was on a long trip, I would stop and correct the pressure.

stymie222

I agree- I thought a dealer was more informed, so I listened.

By the way- Ever try and find a filling station with air these days ?

HOXXOH

I do 3 or 4 corrections locally per year to match seasonal temps. It's not unusual to have a 2-3 lb difference on each side when the car is parked with one side facing the sun.
When I'm traveling (usually in the Summer), I'll make one adjustment once I leave Arizona and leave it there for the duration of the trip. Generally, the pressure tend to normalize in the 32-35 range during the first hour of driving.
The OP just had a much wider temperature spread than normal and got results that reflected the same. No big deal and he correctly compensated. His tire dealer was the problem when he was told to use 34 psi cold. The current 30 psi is where GM says it should be when cold. Then adjust as necessary when local conditions make 20-30 degree seasonal swings.

EVRose

Or try to find one thats free. There are a few around here that actually charge .50 for air. Several years ago I bought an air compressor that I pretty much only use for filling tires.

Dano523

Ditto,

As for pressure, The tires I run are most happy at 35psi when warmed up (side wall flex), so my cold temps are right around 31 psi cold.


So for me on that note, slightly over fill the tires the night before, then in the morning when the tires are cold and the car sitting in the garage, drop the pressure down to what I want to run then cold.

Also, if you do need to add some air if you let more air out than you intended to, then get a spare air bottle (you can build one out of a old freon bottle or buy a spare air bottle), fill it up the night before, and leave it in the garage over night to get as cold as the tires as well. When the tires are warming up, or you are pushing in hot air from an air compressor, your tire pressures are going to be all over the map when then the tires cool back down again.

Simply, your working with cold tire pressure to begin with, then as the tires warm up, the pressure will increase. And yes, it normal for the pressure to drop in the tires from hotter summer times, to colder winter times, and as the outside temperatures take the drastic swings per season, then the cold tire pressures re-adjusted for each season.

ICU2TV

Had this same issue while traveling in Nevada from Las Vegas to Denver. Stop to let out air from all the tires down to the recommended pressure then when I got back to Denver I had the dealer fill them back up to normal for this area.

temp outside was between 80 and 104 degree while this happened.

ls1121

I agree 30 psi cold is the answer.
On another note I have the most comfortable tires made on my car, Michelin Super Sport non-run-flats, yes normal tires and so far I have not had to mess with my tire pressure like I did with my Michelin run flats I used to have. A flat tire does not scare me. I have the green slime kit in my trunk if you want to call it that and if needed my air will be free. Over-inflation could be really bad in the rain.

VET4LES

30 year around for me. That's what the owners manual says and in sunny San Clemente it works.

cclive

The dead of winter...68 degrees. The brutal heat of summer...74 degrees.

AORoads

And flowers and trees that bloom in January. Really tough conditions there, Les.

(I'll never forget returning from a trip in middle January and smelling something that I thought was perfume. It was. A different, natural kind: real flowers blooming.)