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Tire age comes from the DOT number on the sidewall: for tires made after 1999, the last four digits tell the week and year of manufacture.
For the full breakdown, see our best Vintage Style Tires guide.
Figuring out how to age a tire comes down to one string of characters on the sidewall — not your purchase date, not the mileage, and not how much tread is left. Every U.S.-market tire carries a DOT Tire Identification Number, and for tires built after 1999, the last four digits of that code give you the exact week and year the tire was manufactured.
That date matters more than most drivers realize: rubber degrades even when the tire looks fine, so tire age is a safety issue separate from tread wear. The whole check takes a minute or two per tire.
How To Read Tire Age From The Sidewall
Reading the age from a tire means decoding the DOT Tire Identification Number (TIN), and the method is the same for passenger cars and light trucks. Start by finding the DOT marking — the string of letters and numbers stamped into the sidewall of every tire sold in the U.S.
- Write down the last four digits of the DOT code. They read as
WWYY: the first two digits are the week of manufacture, the last two are the year. A code ending in2319was built in the 23rd week of 2019. - If the visible sidewall shows only part of the code, check the inner sidewall — some tires print the full DOT/TIN on the inside, out of sight.
If you end up with four digits, you’ve found the tire’s date. Two mistakes trip people up here. The purchase date is not the age — the production date is what counts, and a tire can sit in a warehouse before it ever reaches your car. And different production dates on one vehicle are normal, so check every tire, including the spare.
When Is A Tire Too Old To Drive On?
The honest answer is a service window of about six to ten years, measured from the manufacture date rather than the day you bought the tires. NHTSA (National Highway Traffic Safety Administration) warns that tire aging happens as rubber and internal components change over time due to service, storage, and environmental conditions — and that aged tires are more prone to failure.
The specific numbers vary by who’s advising. Edmunds reports that automakers including Ford, Nissan, and Mercedes-Benz recommend replacement at six years after production, while tire makers such as Continental and Michelin advise replacement by ten years, with annual inspections starting at year five.
| Guidance Source | Replacement Recommendation |
|---|---|
| Ford, Nissan, Mercedes-Benz | Replace by 6 years after production |
| Continental, Michelin | Replace by 10 years; inspect annually after year 5 |
| NHTSA | Aged tires are more prone to failure; follow maker guidance — typically 6–10 years |
Tread depth never resets this clock: a 12-year-old tire with plenty of tread is still a 12-year-old tire. Near six years, schedule a close inspection; past ten, every source above agrees it’s time to replace.
Signs Of Aging Damage You Shouldn’t Ignore
The date code is the starting point, but the sidewall tells the rest of the story. A tire inside the ten-year window can still be finished, and one past it can fail without visible warning — the age limits exist because the damage often isn’t obvious.
Inspect each tire, front and rear, plus the spare, for:
- Sidewall cracks, or cracks between the tread blocks
- Bulges or blisters, which signal internal separation or a broken belt
- Dry rot — the dull, brittle, alligator-skin look of aged rubber
- Uneven wear, which shortens a tire’s real service life
If the DOT code is unreadable or partial, check the inner sidewall before assuming the tire is undated.
When a tire does need replacing, the date matters at the store too — a “new” tire that already carries a three-year-old date code has three