How Often to Replace Your Tires

Tires have two expiration clocks running at the same time... tread wear and age. Most people only think about tread, but age matters just as much. The rubber compounds in tires degrade from UV exposure, ozone, and heat regardless of how much you drive. Most tire manufacturers and NHTSA recommend replacing tires after 6 years from the date of manufacture, even if the tread looks fine. After 10 years, they should be replaced no matter what... the rubber has hardened and lost its grip. For tread wear, the legal minimum in most states is 2/32 of an inch, but traction starts degrading well before that. At 4/32 inch, wet weather braking distance increases significantly. The penny test is the quick check: insert a penny into the tread groove with Lincoln's head pointing down. If you can see the top of his head, you're at or below 2/32 and need new tires now. A quarter works better as a safety margin... if you can see the top of Washington's head, you're at 4/32 and should start shopping. Most all-season tires last 40,000 to 70,000 miles depending on the tire quality, driving style, and alignment. Performance tires use softer rubber for better grip and wear faster... 25,000 to 40,000 miles is common. Tire rotation every 5,000 to 7,500 miles (usually every other oil change) evens out wear between the front and rear tires and can add 10,000 to 15,000 miles to a set. Alignment is the other factor people miss. If your car pulls to one side or you see uneven wear across the tire face, the alignment is off and it's chewing through rubber on one edge. A $100 alignment can save you from buying tires a year early. Always replace tires in pairs (both fronts or both rears) at minimum. Mismatched tread depths between left and right cause handling problems and confuse ABS and stability control systems.