Owner's manuals usually recommend to check the tires' air pressure weekly.
air pressure
No -- Keep the same recommended air pressure in your tires at all times, but check and add air when the tires are cool and have not been running. Use a tire pressure gauge.
Low pressure.
If air is escaping from your tires then you have a leak. Repair the leak and no more air will escape. This is not to say you never have to check the air pressure. Tires are made from a porous material and as such will loose a very small amount of air even under the best of circumstances. Check the pressure on a regular basis.
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Air expands when heated so therefor increases the preasure
It depends on the tire type and the load of the vehicle. Tire pressure is the amount of air in a tire that inflates the tire to the maker's specifications. For specific tire pressure on a specific vehicle, please look at the sidewall area, as most tires display the recommended pressure according to maximum load.
Even though all four tires have the correct tire pressure, the light will stay on if the pressure in the spare tire is incorrect. This is because of a sensor in the tires.
The air pressure inflates the tire and holds it away from the rim.
fill the tires with air to the proper pressure.
when they are cold....