How to Maintain Proper Tire Pressure in a Car in Winter

Checking the air pressure of your car's tires is a simple thing to do. All it takes is a few dollars for the pressure gauge, a couple of minutes to check the pressure of each tire, and then a trip to the gas station to get each tire to the correct pressure. This is important because the closer your tires are to the manufacturer's suggested guidelines, the better your car will handle, the more evenly your tires will wear, and the longer the tires will last. This is incredibly important in the winter.

Maintaining the correct air pressure in cold weather is a bit more difficult than when the temperature is warm. This is because as the temperature drops, the air temperature inside your tires does, too. This decrease in temperature causes the air to contract, which lowers the air pressure in your tires. After driving for a bit, the air heats up again, but only until you stop. As the tires cool,
the air pressure once again drops.

It can feel like a losing battle because for every 10 degrees Fahrenheit the temperature drops, your tires can lose about 1 pound per square inch (PSI) of pressure. Since it is generally recommended to keep your tires within 5 PSI of the recommended pressure, it becomes more important in winter to check your tires regularly.

Pressure can be affected not just by the generally lower winter temperatures, but also by variances during the day. If the overnight low is below zero, and you set your tire pressure accordingly, you may find that in the afternoon, once the temperature has risen to 30 degrees, your tire pressure has also gone up. If you set your tire pressure in the afternoon, you will then find your tire pressure too low the next morning as you head off to work.

The key to maintaining correct tire pressure in the winter is to keep an eye on the thermometer outside and adjust accordingly. If you encounter a midwinter temperature bump, you can lower your tire pressure to compensate. If you find yourself in the middle of a cold spell, increasing tire pressure is recommended to maintain control and grip on icy roads.

Because of the large difference between day and night temperatures, as well as those in the sunlight or shade, you will want to check your tire pressure more often than you would when day/night temperature swings aren't as drastic. This is also recommended for people who have heated garages for their cars, as this false "hot" read will give an overestimate of your tire's pressure, compared with when it is out in the cold.

Finally, knowing what is meant by recommended pressure is also key. A manufacturer's recommended air pressure for your tires is the cold temperature, not the pressure after you've been driving for a few minutes. Using this measurement, as opposed to a mid-afternoon measurement, will ensure that your tires aren't always running low.


Photo courtesy of Highways Agency, flickr