How to find your DOT code
Look on the lower sidewall for the letters DOT followed by 8–13 characters. The last four digits are the date: the first two are the week of the year (01–53) and the last two are the year. So 3224 means the tire was cured in the 32nd week of 2024 — early August.
Regulations require the full DOT code including the date on only one sidewall. The other side often carries a partial code without the date. If you cannot find a four-digit date, walk around and check the inboard face.
Why tire age matters even with full tread
A tire ages chemically whether it is driven or sitting in a warehouse. Antiozonants like 6PPD slowly migrate out and are consumed, oils evaporate, and the polymer network stiffens and loses its ability to flex without cracking. A tire with perfect tread but a ten-year-old date code can have significantly reduced wet grip and a real risk of sidewall or tread-belt separation.
Age guidance (industry consensus)
- 0–5 years: normal service life; judge by tread and condition.
- 6 years: begin annual professional inspection regardless of tread.
- 10 years: most manufacturers and safety bodies recommend replacement even if unused.
- Buying “new” tires: insist on a date code under 12 months old. A discounted tire with a 4-year-old code is old stock, not a bargain.
This is one of the three markings that actually matter when buying — the full set is covered in how to read a tire sidewall. Storage conditions matter too: heat, sunlight, ozone from electric motors, and contact with oils all accelerate ageing, which is why a garage-stored spare can outlast a tire mounted on a car parked outdoors.