Cold Weather Tire Pressure

Any one with a working knowledge of automobile maintenance will know that tire pressure should always be checked while the tire is cold – meaning not driven on for at least two hours. But cold is a relative term and winter temperatures can quickly go from cold to too cold.

The air in a tire expands and contracts with temperature. Since the inner volume of the tire stays relatively constant, the air pressure increases with higher temperature and decreases with lower temperature. Filling your tires with Nitrogen is one way to help minimize these fluctuations. Nitrogen expands and contracts far less than air.

With winter upon us, you may notice that your tires appear low on air, or the Tire Pressure Monitoring System (TPMS) may be flashing a warning that your tires are low on air. For each ten degrees of temperature change the pressure in an air-filled tire will change by one pound. So if you last checked your tires in the fall when it was in the 70’s and now it’s in the 20’s, your tires have each lost about five pounds of air pressure.

Considering the hazards winter affords; snow, ice, wind and rain, you should pay more attention to your tires in the winter than during any other time of year. So check the driver’s door jamb or the owner’s manual for the recommended tire pressure; make sure the tires are cold; and check your tires using a quality tire pressure gage (dial or digital are most accurate). If your tire pressure light is on, fill all the tires to the proper pressure and check your owner’s manual for how to reset the light. Chances are it will reset itself after driving a few miles. Last, don’t forget your spare.