When was the last time you checked the air pressure on your car’s tires? How about the tread level?

“We’ve become so reliant on the car technology telling us when we have to do something, we haven’t done our own preventive maintenance,” said Ryan Pietzsch, a program technical consultant for driver safety at the National Safety Council. “You should be looking at your tires at least once a month.”

Tire-related crashes led to 622 deaths in 2021, the National Highway Traffic Safety Administration says. Let’s put the rubber to the road and learn more about tire maintenance.

Tire pressure

Every car has a recommended tire inflation level. You’ll find it on a sticker on the driver-side doorjamb. It’s also listed in the owner’s manual.

The numbers are measured as PSI, or pounds per square inch. Follow what’s listed on the car instead of what’s marked on the tire itself, experts say.

Ready to check the pressure? Begin by unscrewing the cap on the valve stem. Then, fit the gauge onto the valve stem and look for the air pressure reading.

If the PSI matches the recommended amount, you’re good to go. If it’s low, head to a service center or gas station.

Make sure to check the air pressure before you head out for a road trip. You also may need to check it more frequently if you live in a cold-weather area – winter temperatures can cause tire air pressure to drop.

Tread

Worn tire tread can lead to flats and dangerous blowouts.

The depth of a tire’s tread is measured in 32nds of an inch. New tires typically have depths of 10/32 or 11/32 of an inch.

The NSC recommends replacing your tires:

• At 2/32 of an inch if you typically drive only on dry pavement.
• At 4/32 of an inch if you regularly drive when it’s raining.
• At 6/32 of an inch if snow or slush are possible.

Don’t have a tread indicator or time to visit a mechanic? An easy, time-honored test is to place a penny upside down into the tread grooves across the tire. If the top of Abraham Lincoln’s head is visible, it’s time to replace the tire.

Tire life

Most manufacturers recommend replacing your car’s tires after six years, Pietzsch said.

To check the age of your tire, locate the Department of Transportation tire identification number, or TIN, on the sidewall. (The number may not appear on both sides of the tire.)

Look for a code that begins with DOT. The last four digits will reflect the week and year the tire was made. For example, “2620” would mean a tire was manufactured in the 26th week of 2020.

Have your tires rotated regularly so they wear more evenly. Most vehicle owner’s manuals recommend rotation every 5,000-8,000 miles, according to the NHTSA.

Spare thoughts

Does your car have a spare tire?

Pietzsch says many newer models don’t come with one, so you’ll want to take a look.

If your car has one, check whether it’s a full-size spare or a “donut” spare intended for short-term use. If it doesn’t come with a spare, see if it has an aerosol emergency tire inflator (which won’t work for blowouts).

And remember: “Donut” spares should never be placed on front tires. Because they’re usually smaller than regular tires, donuts can’t safely handle steering, stopping, and the additional weight and pressure on the front of the vehicle, Pietzsch said.

Include the spare in your regular tire checks so you know that, if you need it, it’s ready to help you get home safely.

Driving habits

Good driving habits can help extend the life of your car’s tires – and make you safer. What do we mean by good habits?

“Following speed limits,” Pietzsch said. “Taking corners safely and appropriately. And if you hit a curb or have a strong collision with a pothole, take a look at your tire right away.”

These kinds of collisions may cause small bubbling or bulging in the sidewall of a tire. If you see an air bubble, have the tire replaced immediately to avoid a potential blowout.