How to read a tyre DOT code and find out how old the tyres are

Where to find the date

On the sidewall look for the letters DOT followed by a string of letters and digits. The date is the four digits at the end of that string, sometimes in a small oval. The full code with the date is often moulded on one side of the tyre only, and the other side carries a shorter code without it. If you cannot find the date, look at the inner sidewall: turn the steering wheel to the lock or crouch behind the wheel.

How to read it

• The first two digits are the week of the year (01 to 52), the last two are the year. 1219 is week 12 of 2019, around the middle of March 2019.
• Tyres made before 2000 have a three-digit date, the week plus one digit for the year, often followed by a small triangle. Such a tyre is more than 25 years old and must be replaced.
• The letters and digits before the date show the plant and the tyre type. You do not need them to find the age.

How old is too old

Rubber ages even when a tyre is not used. Heat, sunlight and long parking speed it up, so tyres age faster in a hot country. There is no single rule: some tyre and car makers recommend replacement after 6 years, others after 10, and many advise a yearly inspection by a professional from the fifth year on.

In practice: under 5 years is fine if the tyre looks fine; around 6 years is a reason to inspect it and to negotiate; 10 years is the time to replace it, whatever the tread depth.

Check all the tyres, and the spare

Read the date on all four tyres and on the spare. The spare is often the oldest, and it is the one people forget. Tyres on the same axle should be of the same make and model and of about the same age. A mixed set, or one new tyre among old ones, suggests the previous owner replaced tyres only when they failed. Check that the size, load and speed markings match the sticker on the door pillar or the owner’s manual.

What else the tyres tell you

• Cracks: fine cracks in the sidewall or between the tread blocks mean the rubber is old and hard. Replace the tyre, whatever its date says.
• Bulges or bumps on the sidewall: internal damage from an impact. Replace at once.
• Uneven wear: an inner or outer edge worn more than the rest points to an alignment or suspension problem; a worn centre to over-inflation; both shoulders worn to under-inflation; patchy ‘scalloped’ wear to tired shock absorbers.
• Tread depth: the legal minimum in many countries is 1.6 mm, but grip on wet roads falls well before that. Treat tyres at about 3 mm as nearly due.

Use it to negotiate

A set of tyres is a real cost, so old or worn tyres are a fair and easy point to negotiate. Find the price of a set of the same size and ask for it to be taken off the price of the car. Photograph the DOT codes so you can show the seller what you found. More checks are in How to check a used car before you buy it.