Tire date code and UTQG ratings
To find a tire's age, look for the DOT code on the sidewall. The last four digits are the week and year it was made: 2910 means the 29th week of 2010.[1 · Oct 29, 2026]
Reading the DOT date
- The code starts with DOT, then the plant and size codes, and ends with the four-digit date.[1 · Oct 29, 2026]
- NHTSA's example: 0308 means the third week of 2008.[2 · Oct 29, 2026]
How old is too old?
NHTSA notes that some vehicle and tire manufacturers recommend replacing tires that are 6 to 10 years old, regardless of tread wear.[2 · Oct 29, 2026] For trailer tires, Carlisle says to replace them after five years in all cases.[3 · Oct 29, 2026]
UTQG: treadwear, traction, temperature
Passenger tires carry Uniform Tire Quality Grading on the sidewall.[1 · Oct 29, 2026]
- Treadwear is compared with a control tire graded 100, so a 200 tire should last about twice as long in the government test.[1 · Oct 29, 2026]
- Traction is graded AA, A, B or C.[1 · Oct 29, 2026]
- Temperature is graded A, B or C.[1 · Oct 29, 2026]
How tires on the market spread across the grades, according to NHTSA:[2 · Oct 29, 2026]
| Treadwear grade | Share of tires |
|---|---|
| Below 200 | 15% |
| 201 to 300 | 25% |
| 301 to 400 | 32% |
| 401 to 500 | 20% |
| 501 to 600 | 6% |
| Above 600 | 2% |
| Grade | Traction | Temperature |
|---|---|---|
| AA | 15% | n/a |
| A | 77% | 62% |
| B | 7% | 34% |
| C | not listed | 4% |
NHTSA doesn't list a share for C traction; its AA, A and B shares add to 99%.
Winter symbol
The mountain and snowflake symbol means the tire passed a snow traction test. Winter tires are designed for temperatures below 40°F.[1 · Oct 29, 2026]
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Sources: 1. Tire Industry Association, Reading a tire sidewall. 2. NHTSA, Tires. 3. Carlisle Transportation Products, Trailer tires: tips and best practices (PDF). Checked Oct 29, 2026. Size dimensions, revolutions per mile and speedometer figures are our own arithmetic from the size code. Trademarks belong to their owners; figures are restated in our own words and tables, not reproduced.