How Do I Check Tire Pressure?

In an ideal world, the air pressure in your tires is something you don’t think about more than, say, a few times a year. But that is not the world we live in. The most conscientious drivers check their tire pressure at least once a month, if not every week. But some mechanics say it’s okay to check less frequently, such as when the seasons change, when you change your oil, or before long trips. Bottom line is this: never assume your tire pressure is good, and when in doubt, check! Why is proper air pressure (measured in psi, or pounds per square inch) so important? Not enough pressure causes poor gas mileage and increased chance of blow out from overheated tires. Too much air pressure can make tires bounce, reducing traction and resulting in a bumpier ride for you.

To check tire air pressure in the simplest way possible, you’ll need two things:

1).  A tire pressure gauge, conveniently kept in your glove box.

2).  Your vehicle’s Owner’s Manual.

Gauges vary in technological complexity. The most traditional ones have a silver knob with an open end that fits over your tire’s valve. At the other end of the gauge, a white plastic stick with measurements shoots out in response to the tire’s pressure when you fit the knob onto the valve. The number on the white plastic stick is your reading. Fancier gauges provide digital readings. In deciding between these two options, price and availability are obviously factors. The low-tech, “pencil style” gauges cost about $6; the digital versions can get up to $20.

Once you settle on a gauge, checking the pressure is pretty straightforward:

1).  Before you start driving, when your tires are still cold, consult your manual, find out what pressure your tires should be, and fit the measuring part of the gauge over your tire valve. Some cars even have a sticker in the driver’s side doorjamb with tire pressure requirements, so you don’t even have to crack the manual.

2).  Unscrew the cap from the tire valve and fit your gauge over it snugly. Get the reading immediately, before too much air escapes. If the pressure is off by even one psi in either direction, try to get it exact!

3).  If pressure is too high, release some of the air by pushing gently on the valve and letting out small bits at a time. If the pressure is too low, you can fill up at any gas station.

But although tire air is still free in some places, be prepared with at least a dollar’s worth of quarters just in case. The only guaranteed free air these days is the air you breathe, and somebody’s probably still trying to figure out how to charge for that.