Originally Posted by rexva
This probably sounds very stupid, but bear with me...
I take the pressure "cold", say in the morning, and it's low.
So I drive to the gas station to use the air machine... now they are warm. So how do I know what pressure is right?
Originally Posted by BarManBean
Buy a compressor. That's really the only way to actually fill them up "cold".
Where are you at in NOVA, anyway?
Compressor is the best way, even just a portable pump is fine, but what I used to do before I got one is this:
1) Check pressure. Let's say you're looking to get 35/33 and you're currently reading 33/31. That means you're down 2 PSI all around, right?
2) Drive to the gas station. Hopefully it's pretty close by.
3) Check the pressure again. It'll probably be reading 35/33 or something like that by now. Make a note of the new pressure and add 2 to it. So in other words, after you arrive at the gas station, you're reading 35/33. Fill your tires to 37/35 instead because remember, you were missing 2 PSI before. If you're not sure, you should add some more air in because it's always better to overinflate a bit. You can always let air back out without a pump!!
4) The next day, after the car is completely cool, check the pressure again. Hopefully it's on target. If it's too high, let out some air to the appropriate target pressure. This is why I said to overinflate a bit to be sure. You can always let out the air now.