Breakdown: Why tire pressure changes in cold temperatures

Updated: Jan. 13, 2020 at 4:01 PM CST
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MEMPHIS, Tenn. (WMC) - If your TPMS (tire pressure monitoring system) indicator light illuminates during a cold blast, it can be bothersome.

In this Breakdown, we will discuss the effects cold temperature can have on your tires and tips that will hopefully help your tires operate at maximum performance.

Tire pressure can decrease about 1 PSI (pound per square inch) for every 10 degrees the temperature decreases. It doesn’t mean that you are losing air from your tires but more that the air inside the tire condenses, causing the air to take up less space when it’s cold.

Tires can also lose about 1 PSI per month due to air seeping out at the edge of the rim and through the tread itself.

This combination of those two factors can cause the air pressure in a tire to fall near 25-percent below the recommended pressure level. This is what triggers your tire pressure light to illuminate on your dash.

In general, in cold weather, your tire pressure will decrease about 1 to 2 pounds of pressure for every 10 degrees Fahrenheit the outside air temperature drops,

If afternoon high temperatures reach 45 degrees but drop to 15 degrees at night, your tire pressure will vary 3 PSI. This doesn’t include natural air loss. This is why it’s not unusual to have the low-pressure indicator light go on first thing in the morning since it’s usually coldest overnight.

The tire pressure indicator may shut off on its own after you have driven 20 minutes or more as the air in your tires warms and expands and the right inflation level stabilizes.

Either way experts recommend getting your pressure checked even if the indicator light shuts off.

The TPMS light means your tires are at least 25-percent below the proper air pressure. According to experts, this could be a risk, especially if the load you’re carrying is close to your car’s maximum capacity. Experts say there is a higher chance of your tires failing, and it may increase the wear and tear of your tires. In addition, gas mileage could also suffer.

Experts warn that if the warning indicator is flashing, this is could mean a problem with the vehicle’s TPMS system itself, not your tires, and experts suggest you take your car in for a diagnostic.

Another reason your TPMS indicator may flash or illuminate if your vehicle’s on board computer can’t detect the sensor itself because you’re using a spare tire. They don’t usually have TPMS sensors.

Tips on how to maintain tire pressure

  • The best time to check your tire pressure is in the morning before your car has been driven.
  • Record the psi for each tire.
  • Check pressures with accurate gauge.
  • Fill to recommended psi.

Experts also suggest once a month having your pressure checked during the winter when the tires are cold.

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