How Old Are My Tires? Reading the DOT Date Code
The last four digits of your tire's DOT code are the week and year it was made — 3523 means week 35 of 2023. Industry guidance: annual professional inspections from age 5, most manufacturers recommend replacement between 6 and 10 years, and 10 years is the ceiling regardless of tread.
Finding the code
On the sidewall, look for letters starting with DOT, followed by plant and size codes. The date is the final 4-digit group — on some tires it's only molded on one side.
Example: DOT U2LL LMLR 3523 → week 35 of 2023.
Type yours into the DOT date decoder for the exact date, the tire's age today, and what to do about it.
Age guidance the industry actually uses
| Age | Status |
|---|---|
| under 5 years | normal service — watch tread and pressure |
| 5–6 years | professional inspection every year; trailer tires: plan replacement |
| 6–10 years | many manufacturers recommend replacement regardless of tread |
| over 10 years | replace, period |
A 3-digit date code means the tire predates 2000 — replace it immediately.
Why age matters even with good tread
Rubber degrades from the inside out: oxidation stiffens the casing whether or not the tire turns a mile. Sun, heat and sitting accelerate it — which is exactly a trailer tire's life. That's why trailer guidance says 5–6 years even when the tread looks new.
Tread has its own clock too — check both: tread depth guide. Time for a set? Find installation near you.