How do I know when my tires need replacing?
Short answer
Replace a tire when its tread is worn to 2/32 of an inch, which is when Lincoln's whole head shows in the penny test or the tread is flush with the built-in wear bars. Start shopping at about 4/32 inch (the top of Washington's head shows on a quarter), because wet braking and hydroplaning resistance drop off well before a tire is fully worn.
Safety first. Replace any tire with a bulge, a cut or cord showing on the sidewall right away, whatever its tread depth. Worn tires stop longer and hydroplane more easily on wet roads, so slow down in the rain until you can replace them.
On this page
Step by step
- 1
Do the penny test
Put a penny into a tread groove with Lincoln's head upside down and facing you. If part of his head is covered by tread, you have more than 2/32 inch left. If you can see the top of his head, the tire is worn out and should be replaced.
- 2
Do the quarter test
Do the same with a quarter, Washington's head down. If you can see the top of his head, you have about 4/32 inch left. The tire is still legal in most places, but it's time to start shopping.
- 3
Check several spots on every tire
Test the outer, center and inner grooves at a few places around each tire. Uneven wear, such as one edge worn more than the other, can mean low pressure or an alignment problem that will wear out new tires too.
- 4
Look for the tread wear bars
Most tires have small raised bars running across the bottom of the grooves. When the tread is worn down flush with those bars, the tire is at 2/32 inch and done.
- 5
Check the tire's age
Find the DOT code on the sidewall (it may be on the inner side). The last four digits are the week and year it was made, so 2219 means the 22nd week of 2019. Old tires can need replacing even with tread left.
Quick reference
| Tread depth | What it means | What to do |
|---|---|---|
| 10/32 to 11/32 in | Typical new tire | Nothing |
| About 4/32 in (Washington’s head shows) | Wet grip noticeably reduced | Start shopping |
| 2/32 in (Lincoln’s head shows, flush with wear bars) | Worn out | Replace now |
Wet roads are where worn tires show it
The grooves in your tread carry water out from under the tire. As they get shallower, the tire can’t clear water as fast, so it stops longer and is more likely to hydroplane. That’s why Consumer Reports suggests shopping at 4/32 inch instead of waiting for the legal limit, especially before a rainy season or winter. If you drive on snow, see winter tires vs. all-season too.
When to see a pro
Have a tire shop look at the car if the tires are wearing unevenly (one edge, the center, or in patches), if a tire keeps losing air, or if you see any sidewall damage. Uneven wear often means a pressure, alignment or suspension problem that new tires won’t fix on their own.
Common follow-up questions
What is the legal minimum tread depth?
Several U.S. states require tires to be replaced at 2/32 of an inch, and the U.S. Department of Transportation recommends replacing them at that depth too. Check your own state's rule, but treat 2/32 inch as the end of a tire's life everywhere.
How much tread does a new tire have?
Pep Boys says new passenger tires typically start with about 10/32 to 11/32 of an inch of tread. Tread depth in the U.S. is measured in 32nds of an inch.
Why replace tires at 4/32 inch if 2/32 is the limit?
Wet performance drops as tread wears. Consumer Reports cites an AAA study that found tires worn to 4/32 inch could add up to 87 feet to a passenger car's stopping distance on wet roads and reduce control by 33 percent. Shopping at 4/32 gives you time to compare prices before the tires are unsafe.
How old is too old for a tire?
Rubber ages even when a tire isn't used much. Tire retailer SimpleTire says most tires last about six to ten years from the date they were made and recommends replacing them around six years regardless of tread. Your tire maker or owner's manual may give its own limit, so check that too.
Sources
- 1.Consumer Reports: Tires Don't Have to Be Worn Out to Lose Traction in Wet Weather
- 2.Pep Boys: Check Tire Tread Depth with the Penny Test
- 3.SimpleTire: How to Read a Tire's DOT Code
General information only, not a diagnosis. Your owner’s manual comes first. How we write these