How to Check Your Tire Pressure

How to Check Your Tire Pressure

Everything from fuel economy to emergency braking, handling, and vehicle load capacity is highly dependent on your tires being inflated to the right air pressure. Out-of-specification pressure can compromise all of the above, not to mention seriously shorten the lifespan of your tires.

Lacking the tools necessary to check tire pressures, or unsure about any of these instructions as they apply to your vehicle? Stop into Family Tire Pros in American Fork, and our tire technicians will be happy to lend a hand.

Step 1: Identify Your Vehicle’s Specifications

A common misconception is that the need-to-know tire pressure information is found on the sidewall of your tires. In fact, there’s a lot of jargon there, most of which is important to tire pros like us, but your vehicle’s tire pressure specification will not be indicated on your tires.

“Max” pressure information is available on the tire sidewall, but that’s not the number to go by.

For the right tire pressure information, you’ll need to refer to the card information that’s on the driver’s side doorjamb of any vehicle. Open your driver’s door and find the card/plaque that’s glued or screwed into the body of your vehicle. On the card will be your vehicle’s target tire inflation pressures for both front and rear tires, expressed in “psi” (pounds of pressure per square inch).

It’s important to note that this is your vehicle’s starting or “cold” tire pressure. Tire pressure changes when in use – specifically, it increases once the vehicle is moving. Pressure also fluctuates according to outside temperatures. For example, a sudden drop in temperature will trigger a corresponding drop in tire pressure as the air condenses.

So the best time to check your tire pressures is before setting off for the day, or after a period of time with the vehicle stationary.

After identifying your vehicle’s tire pressure specifications, it’s time to get down to the business of checking tire pressures.

Step 2: Check Your Tire Pressure

There are two ways to check your tire pressure, one of which doesn’t require you to move from the comfort of your driver’s seat, so let’s explore that one first.

If you own a modern vehicle with a digital information screen, either in the instrument cluster or on a central screen on the dash (i.e., the same one that offers navigation), then it’s likely that you have a digital tire pressure readout.

The tire pressure display is typically found in the “Vehicle Info,” or “Settings” area of the onboard computer (terminology varies). If not findable, refer to your vehicle’s owner’s manual for instructions on how to navigate to the tire pressure display screen.

If you’re lucky enough to have one of these readouts, compare the displayed pressure values to the information you sourced from the vehicle information card, then adjust as necessary (see Step 3). Job done!

If your vehicle is a bit older and doesn’t provide tire pressure information digitally, then you’ll need to go “old school” and get involved at ground level.

  1. Grab your choice of tire pressure tool.
  2. Find the tire valve stem on each wheel and unscrew the cap.
  3. Press your tire pressure device into the top/opening of the valve stem to prompt a reading on your device. Be sure to press the tool evenly and firmly onto the valve stem. If you hear hissing as you’re attempting to take the reading, then air pressure is escaping, and this can result in an inaccurate pressure reading.
  4. Repeat the process for all four wheels and tires. Don’t assume that one reading is representative of all four tires – pressure can vary widely left to right and front to back. Don’t forget to reinstall your valve stem caps for all four tires.

If your tires are at or very close to vehicle specification (within ~1 psi), then you’re good to go. If you’ve found pressures are uneven around the vehicle, or substantially different than vehicle specification, then you’ll have to do some adjustment work.

 

Step 3: Adjust Tire Pressure

Finding tire pressure that’s too low is most common, but sometimes tires are inflated well above vehicle specification. For example, if tires were last inflated in moderate temperatures, and then a sharp rise in temperature occurred, tires can become overinflated (too high in pressure).

If you’ve found your tires above vehicle specification, then you can release air as needed. Gently press a key or other pointy object into the top of the valve stem and release air (you’ll know you’ve hit the mark when you hear hissing). Release a little bit of air at a time, and recheck your tire pressure. Repeat the sequence until you’ve hit your vehicle specification.

If tire pressure is too low, then your path is a little bit more arduous. A pump is required to re-inflate the tires to specification.

A home air compressor unit is most convenient. These can be plugged into your vehicle’s accessory power outlet and operated.

To maintain maximum vehicle safety and capability, check your tire pressures at least once a month, and/or whenever a notable change in air temperature has occurred.
The Tire Pros are here to help you with any tire pressure issues or questions.