Straight Talk About Recommended Tire Pressure

Skyrocketing gasoline prices put tire pressure into the news. Even Reuters chimed in, letting drivers know that commuting for one year with low tire pressure could translate into $800 in additional gas spending. Yet there is little talk about maintaining recommended tire pressure. It is time for some straight talk on the subject.

How often should I check for low tire pressure?

At the bare minimum, check once per month; if you want to be proactive, check your tire pressure every time you buy gasoline. Depending on your driving habits, this should be once or twice per week.

Is low tire pressure really a problem?

The University of Rochester warns drivers that low tire pressure is not only associated with bad gas mileage, but it also leads to poor handling of the vehicle and tire blowouts. Remember that low tires contribute to tire wall wear, which is a flat waiting to happen. In short, underinflated tires are not just costly but also dangerous.

My tires don't look low; I'm fine. (or: My sensor hasn't gone off; I'm fine.)

Did you know that the average tire loses between one and two pounds of air a month in cool weather? By the time that tires look quite low, they are well past the point of recommended tire pressure. Sensors, too, have had their fair shares of recent recalls. (If you drive a Toyota, you know all about the tire pressure monitor recall in March.) The only way to know for sure is with the judicious use of the tire pressure gauge.

Isn't it enough to use the gauge from the gas station?

Do you entrust your blood pressure measurements exclusively to publicly available cuff, mounted to the outside of a busy phone booth? If the answer is a resounding no, why would you entrust your car's tire pressure to a gauge mounted to the exterior of a busy gas station, where it is most likely not treated very well by various users? If you are serious about keeping your tires properly inflated, buy a good quality tire pressure gauge and keep it in the glove compartment for personal use.

What is the recommended tire pressure for my car?

Each car manufacturer marks down the tire pressure that the driver must maintain for best performance. Check your owner's manual for a recommended tire pressure chart. If you own a used car and the manual is not available, check the driver's side door jamb for a sticker. If all else fails, call the dealership or the manufacturer.

In a pinch, compare the pounds per square inch (PSI) reading to the numbers printed on the tires' side walls. Even though these numbers only warn against overinflating the tire by listing the maximum allowable PSI, it offers a bit of a guideline. Keep each tire at the same pressure level.

Does it matter if I go at high noon to check my tire pressure?

Temperature affects tire pressure gauge readings. Always check when it is cooler in the day, such as earlier in the morning or in the evening. Don't decide to check it in the heat of the day and then let out some of the supposed overage. Hot temperatures lead to a temporary but measurable increase in tire pressure.

By the way, you do realize that all of this also applies to the spare tire in your trunk, right? (You do have a spare tire in the trunk, don't you?)

Sources

Reuters: "Adjusting Tire Pressure Can Save Gas and Money, According to Edmunds.com Study"

University of Rochester: "How to Inflate Tires"

Y!CN: "Toyota Recalls 22,000 SUVs and Pickups Over Tire Pressure Monitors