care4era

I am off on a 1500km journey tomorrow and I think the front tyres are a wee bit flat. I know the right measurement is 34 cold but I do not have something to check when it is cold and the nearest garage is 4kms away or so. Is there anything to go by when the tires are warm?

nycebo

Generally, as long as I am not 'racing' from the garage, I compensate by adding 5-10% to the recommended tire pressure. The next morning, when it's cold, you can slightly deflate the tires to get the desired pressures. For me, I'm 34 up front, 42 in back (like that feel best).

1999Porsche911

You should be running 36F/44R cold. It is hard to determine what the exact hot temp should be since road serfice, tire design, etc play a big roll it that. On a warm tire, if you read 10% higher, you should be close to the correct pressure.

DanDotDan

Rule of thumb: I add 4 pounds for running hot.

Now that we're on the subject, should you adjust the cold tire pressure for ambient temperature? 36 pounds in the middle of August is different from 36 pounds in the middle of February, right?

1999Porsche911

Cold pressure target is based on ambient temperature.

spiderv6

Oh yes, I found this out recently!

I picked my car up in the middle of summer when it was 100 degrees plus here in NJ. The car was PDI'd and the tires inflated appropriately.

A few weeks later I checked the pressures for the first time and found 26/32

The dealership explained it as the efect from the weather when I picked it up.