cold vs hot tire pressures when airing up or down

[DonC]

Say my cold tire pressure is 60 lbs for highway, E rated tires. I go to Death Valley and air down for several days of dirt/washboard roads. Once I hit the highway again and am ready to drive home I want to air up, and my tires will be hot. I've read that hot tire pressures are 3 - 5 lbs higher, so airing up with hot tires I would be looking 65 lbs. Does this sound about right and is this what people do?

I have a 4x4 truck but am seldom on hard core 4x4 roads - but lots of gravel roads. I never used to air down before having my FWC. But now with 1000 lbs in the bed and E rated tires its a pretty jarring ride out to the Racetrack unless I air down.

 

[Squatch]

Normally when I air up I just add air to normal pressure, Then check the tire pressure 1st thing in the am when the tires are cold.

 

[Advmoto18]

Cold tire temp is based on the coldest average for your current location.

The rule of thumb is 1 psi for every 10'F.

The average coldest temp in Death Valley in Jan is 40'F according to NOAA.

If you've air down from your normal 60 psi (assuming you checked your psi in the morning when the tire was cold and it was indeed 60 psi)...and current air temp is say 50F, and your tires are warm, then air up to 61psi. Assuming you can see 1 psi on your gauge.

The difference between the average low and average high for any given month in DV seems to be ~30 degrees. Thus, your air up value for a warm tire will be adjusted 3 psi.

As you can see, not too much of an issue unless you are inflating to tire's placarded max psi and at the tire's max weight.

The real issue is failing to air up upon reaching tarmac and driving at highway speeds with under-inflated tires. An under-inflated tire operated at highway speed is the number one reason for tire failures, regardless how the tire became under-inflated.

 

[ntsqd]

I don't worry about it. A hot tire usually only comes from driving on pavement. In the dirt ours are rarely warmer than ambient unless I've gone really low and am driving way too fast for the air pressure - which I hardly ever do.

 

[SunMan]

I just put in as much air in as I take out (~10 lbs), usually hot when both airing up/down. Tires are usually pretty close to where they should be once cold.

 

[DonC]

good stuff
I like the rule of thumb that if tires are hot and you take out 10 lbs, then put 10 lbs back in, pretty simple

thanks

 

[Marc]

I just put in as much air in as I take out (~10 lbs), usually hot when both airing up/down. Tires are usually pretty close to where they should be once cold.

Ditto on what Suni said.

 

[iowahiker]

My F-150 driven tire pressure is 5 pounds higher than cold after dozens of checks. All my cars had a 3 pound difference between driving warm and morning cold pressure.