Tire FAQ

What is the legal minimum tread depth?

Most U.S. states set it at 2/32". Many experts advise replacing at 4/32" for wet-weather safety. See the tread tests.

How old is too old?

There's no federal limit. Many makers say 6 to 10 years from the DOT date. See the DOT date guide.

What PSI should I use?

Use the number on your door placard, not the maximum printed on the tire sidewall. See the pressure guide.

Can I mix tire brands or types?

It's best to keep all four tires the same, or at least matched on each axle. Never mix winter and summer tires on the same vehicle.

Plug or patch?

The industry-recommended repair is a combination patch and plug applied from the inside, for tread punctures up to 1/4". Sidewall punctures shouldn't be repaired (USTMA).

Is nitrogen worth it?

Nitrogen may leak a little slower, but regular air checked monthly works fine. Correct pressure is what matters.

How long do tires last?

It depends on the treadwear grade, driving style, climate and maintenance. Many tires carry mileage warranties of 40,000 to 80,000 miles.

Related guides

• When to Replace Your Tires
• Door Placard and Correct Tire Pressure
• DOT Date Code: How Old Are Your Tires?

General information only, not a substitute for an in-person inspection by a qualified tire professional. If in doubt, have your tires checked.

Sources

• NHTSA – TireWise / Tire Safety brochure (DOT HS 811 151)
• U.S. Tire Manufacturers Association – Tire Care
• NHTSA – Tires

Last updated October 28, 2026.