Tire Air Pressure

[IROC U]

I have a question about tire air pressure. I know that the recomended air pressure is 32lbs. Is this the recommended pressure for a cold/cool tire or a warm/hot tire. I notice that my tire pressure goes up about 3lbs per tire after about 20 minutes of driving. Also one of my tires always seem to be a little lower than the others. I've had it checked but no problems were found. Any one else experiencing this?

[Zee-Ell-One]

Originally Posted by IROC U

I have a question about tire air pressure. I know that the recomended air pressure is 32lbs. Is this the recommended pressure for a cold/cool tire or a warm/hot tire. I notice that my tire pressure goes up about 3lbs per tire after about 20 minutes of driving. Also one of my tires always seem to be a little lower than the others. I've had it checked but no problems were found. Any one else experiencing this?

Yes I have the same quirk. Believe your hand held tire guage although I do use the TPMS readout to make sure my tires are plus 2 or 3 PSI before I start driving in a sporting mode.

[Jim968]

The manufacturer recommended pressures are always cold pressures. You'll only hear people talking about hot pressures when driving on a race track.

Its perfectly normal to see pressure increases from cold to hot of about 3 lbs when driving on the street. If you were to take the car on the road circuit you would see increases of 6 to 10 lbs, and managing hot pressures would then become an issue.

I assume you're seeing the low pressure on the one tire via the TPMS? If that's the case you might want to invest in a decent tire gauge to check it. Could be a bad sensor if its consistently 3 lbs. low.

[BAD ZL1]

My hand held showed 32, on star sent me an email say to check my low tire pressure. I added 2 psi to the tires. The cars system still shows a bit low.

[hognutz]

32 cold is what is recomended most of the time. that is for optimum tire wear though not performance in any way.

On my corvette the limits of the system were low pressue 25 you got a warning high pressure of 40 you got a warning. so if I were to put say 35 in there cold on a hot summer day they would go over 40 sometimes. 32 seems to work well with the limits of these systems for driving.

the 32psi is taking into acount that during driving the tire will proably achive the 35psi. if you pump them up to say 35 cold then you could get a 38 or 39 psi wile your driving and that could lead to uneven wear depending on the max pressure rating of the tire.

[fielderLS3]

Checking tire pressure for a street car is like checking oil. You do it cold after it has been sitting for a while.

The air pressure in your tires will change approximately 1 PSI for every 10 degrees the temperature changes, up with warmer temps, down with lower temps, just like the old gas law problems you probably saw in high school chem.

[HDRDTD]

Originally Posted by BAD ZL1

My hand held showed 32, on star sent me an email say to check my low tire pressure. I added 2 psi to the tires. The cars system still shows a bit low.

OnStar seems to think that the tire pressure should be 36psi like my 2011 Vert tires.

I doublechecked the tire pressure sticker on the door jam and it stated the normal (cold) pressure should be 32psi.

Go by the sticker on your door jam, not OnStar.