if you want to check to see if your tires need air the service manual of your car warns you against checking the tire pressure when the tire is hot WHY?
friend, i cant tell you the number of times i've slept on the ground with out a sleeping bag or a tent, if you really have the will to do it then go for it.
try a tarp or a sheet of painter's plastic (from a hardware store) and then a few blankets on top of that. when you sleep outside, you'll probably be cold at night and wake up kind of dewy and damp, so make sure you stay warm enough
Because tire pressure changes with temperature. Baseline pressures need to be set while the tire is cold because you have no way of knowing how much the pressure changed with the increase in temperature if they have been driven on.
Tire pressure tends to fluctuate and increase after driving. Therefore, you cannot get an accurate tire pressure reading after your automobile has been driven. Simply check your psi first thing in the morning, or after several hours of being parked, to get the most accurate reading.
Air expands as it is heated. As you drive your tires heat and the tire pressure increases. To do it right the vehicle should sit in the shade for at least 3 hours before you check the tire pressure. This gives you the most accurate reading. Adjusting the tire pressure on warm tires and you will actually be setting the tire pressure a little low. Low tire pressure consumes more fuel, generates more heat, causes more wear, and can cause tire failure. Also, do not use the tire pressure on the tire sidewall. There will usually be a label in the driver's door jam with the vehicle manufacturer's recommended tire pressure. This vehicle manufacturer's recommended tire pressure supersedes the tire manufacturer's recommended pressure printed on the tire sidewall. If all else fails, FOLLOW THE INSTRUCTIONS! Note: Both of my cars have the built in tire pressure monitors. I have personally seen the tire pressure increase up to 4 PSI after the car has been driven for a little while.
