Knowing when to replace tires is one of the simplest ways to stay safe on the road. Worn tires take longer to stop, slide more in the rain and are more likely to fail. Fortunately, a few quick checks tell you exactly where you stand.
Check your tread depth
Tread depth is measured in 32nds of an inch. New tires usually start between 10/32″ and 11/32″. By law in many states, 2/32″ is the minimum. However, wet-weather grip drops sharply well before that point.
- 4/32″ or less: start shopping, especially before the rainy season.
- 2/32″ or less: replace now. The tire is legally and practically worn out.
The penny and quarter test
Place a penny upside down in a tread groove. If you can see the top of Lincoln’s head, you are at about 2/32″. With a quarter, seeing the top of Washington’s head means roughly 4/32″. Check several spots, because tires often wear unevenly.
When to replace tires based on age
Rubber ages even when a tire is not used much. Many manufacturers recommend inspecting tires yearly after five years and replacing them by ten years at the latest. Many experts suggest replacing most tires around six years old. To find the age, look for the four-digit DOT date code on the sidewall. For example, “2321” means the 23rd week of 2021.
How Southern California heat affects tire life
Hot pavement speeds up wear and ages rubber faster. In addition, long freeway miles on the I-5 and I-405 build heat in the tire. Underinflation makes this worse, so check pressure monthly. Read our guide to tire pressure in hot weather for more.
Other signs it is time for new tires
- Bulges, bubbles or cuts in the sidewall
- Cracking between the tread blocks
- Vibration that balancing does not fix
- Uneven wear that exposes cords or steel belts
- Repeated slow leaks
Uneven wear usually means an alignment problem too. Fix it when you buy new tires, or the new set will wear the same way. See our wheel alignment service.
Replacing two tires or four?
Replacing all four keeps handling balanced. If you only replace two, put the new tires on the rear axle for stability. All-wheel-drive vehicles often need all four replaced together to protect the drivetrain.
The U.S. National Highway Traffic Safety Administration has more detail on tire safety and tread wear.
Still not sure when to replace tires?
Stop by our Irvine shop and we will measure your tread and check your tires for free while you wait. If you do need new tires, browse our new tire options or request a quote.
Written by the WTC service team
Wheel & Tire Connection is a tire, wheel and alignment shop in the Irvine Auto Center, serving Irvine, Lake Forest and South Orange County.
