Tire Care: Pressure, Tread, and Rotation

Why Tires Deserve More Attention

Tires affect braking, steering, fuel economy, and ride comfort all at once. They are also the part of your car that is most often neglected, because they rarely announce a problem until it is serious.

Underinflated tires run hot, wear out faster, and can fail at highway speed. Overinflated tires wear down the center of the tread and give up grip. The correct pressure for your vehicle is not the number printed on the sidewall; that is the tire’s maximum, not what your car needs.

Checking Pressure Correctly

• Check them cold — Measure before you have driven, or at least three hours after parking. Driving adds heat and raises the reading.
• Use the door jamb sticker — The driver’s door jamb, fuel door, or owner’s manual states the recommended cold pressure for your vehicle. Front and rear may differ.
• Do not use the sidewall number — That figure is the tire’s maximum load pressure, not a recommendation for your car.
• Recheck monthly — Tires lose about one psi per month in cool weather, and more when temperatures drop sharply.
• Fill in small steps — Add a little air, recheck, and repeat. It is easy to overshoot with a fast pump.

Reading Tread Depth and Wear

Tread channels water away from the contact patch, so depth matters most in the rain. You can check it with a gauge or a penny.

• Depth — Tires are legally worn out at 2/32 inch. Many safety experts recommend replacing at 4/32 inch, because wet grip drops off quickly after that.
• Worn in the center — Usually overinflation, or a lot of highway driving at high pressure.
• Worn on both edges — Usually underinflation.
• Worn on one edge — Usually an alignment problem.
• Cupping or scalloped spots — Points to worn suspension parts or an out-of-balance tire.
• Sidewall cracks, bulges, or visible cords — Replace the tire. Damage like this cannot be repaired.

Rotation, Balance, and Alignment

Rotating your tires every 5,000 to 8,000 miles evens out wear between the front and rear, which is the cheapest way to make a set last longer. Some vehicles use a specific rotation pattern, so check your manual.

Balancing corrects a tire-and-wheel assembly that is out of weight, which shows up as a vibration at highway speed. Alignment corrects the angles of the wheels, which shows up as a pull, an off-center steering wheel, or rapid wear on one edge after hitting a curb or pothole.

When to Replace Tires

Replace tires in pairs on the same axle at minimum. On all-wheel or four-wheel drive vehicles, replacing all four is strongly preferred so the drivetrain is not fighting mismatched diameters.

• Tread at or below 2/32 inch — They are legally worn out and unsafe in the wet.
• Sidewall damage — Cuts, cracks, and bulges cannot be repaired safely.
• Repeated punctures or a repair near the sidewall — The tire has lost the integrity you need.
• Six to ten years old — Rubber ages even when tread remains. The DOT date code on the sidewall shows the week and year of manufacture.
• Wear that will not correct — If a tire keeps wearing unevenly after an alignment, replace it.