With temperatures dropping as we move deeper into fall and near winter, experts recommend checking tire pressure often. Properly inflated tires allow your vehicle to perform optimally, improve overall safety, lead to maximum fuel efficiency, and prolong tire life.
Tires are impacted the “ideal gas law.” If you recall from high school physics, PV=nRT where P is pressure, v is volume, n is quantity of gas, R is the universal gas constant, and T is temperature. Unless you have a leak, one can assume that the volume of a tire and the volume of gas (air) it contains remains constant. However, since temperature and pressure are directly proportional, any change in temperature will change pressure. In the summer, your tires “inflate” as they heat. But in the colder months, your tires deflate –and they may deflate to unsafe or sub-optimal levels.
Tire pressure drops roughly 1PSI (pound per square inch) for every 10 degree drop in ambient temperature. So when we drop from 80 degrees not long ago to overnight lows in the mid 30s, that could be a significant 5PSI drop to your tires’ pressure.
Not sure what your tire pressure should be? Check your auto manual. Appropriate tire pressures are almost always on a decal located on inside the driver’s or passenger’s door, depending on where it was made. Ideal rear pressures may be different from front pressures; don’t assume. Don’t judge tire pressure by appearance; don’t depend on the tire pressure warning lamp that some cars may be equipped with. The best way to check tire pressure is by using a tire pressure gauge, which is available from many outlets online and offline for just a few dollars. Some household pumps and most commercial pumps show air pressure as you inflate your tire(s) there.
And lastly, don’t forget to check your spare tire! A spare tire is susceptible to the same pressure changes as your other tires; it’s important that your spare always be properly inflated in the event you need to use it.
