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Tyre DOT Code:
what is it and how to read it

What is DOT?

How old are your tyres?

How do you read a tyre date code?

Other signs on the tyre

A common misconception about tyre age

FAQs

What is DOT?

DOT is the abbreviation for “Department of Transportation” and indicates a unique tyre code which is a series of 7 to 13 letters and numbers printed on the sidewall of a tyre (the vertical surface of rubber above the wheel). DOT is usually followed by a combination of letters and numbers that provide information on the tyre’s place of manufacture, as well as its type and age.

How old are your tyres?

Information on the age of your tyres is contained in the four numbers at the end of the DOT code. This date code is often encircled by a raised rubber oval. If you see the letters DOT, but they are not followed by any other letters or numbers, look on the other sidewall. Manufacturers are only required to stamp the complete tyre identification number on either the inside or outside sidewall, but not both.

How do you read a tyre date code?

The first two numbers of the 4-digit DOT date code (which, again, appears at the very end of the string of letters and numbers that start with DOT) indicate the week that the tyre was manufactured. The last two numbers of the date code tell you the year of manufacture. In the example below, the date code is 0517, which means that the tyre was made in the 5th week of 2017. If the date code has only three digits, it means that your tyre was manufactured before the year 2000, when a different system was used.

Other signs on the tyre

Apart from the DOT designation and date code, you will find other letters and numbers on your sidewall containing additional information about your tyres. These include the other letters and number in the tire identification code itself, which are between the DOT marking and the date code. These additional characters come in either two or three blocks.

The first block tells you the plant where the tyre was manufactured.
The second block is a tyre size code.
The third, which is optional, is an internal individual product code defined by the tyre manufacturer.

Elsewhere on the sidewall, the most common markings are for tyre size, speed index and load index. These numbers are usually bigger than the DOT code and generally appear in the following order: nominal section, width, height-to-width aspect ratio, wheel diameter, load index and speed index. The load index is a 2 to 3-digit number that can be used (by referring to load index chart) to look up a tyre’s maximum load when properly inflated. The speed index is a letter that can be cross-referenced to learn the maximum safe speed for a tyre.

A common misconception about tyre age

A common misconception is that high-mileage tyres are immune to ageing. While some have anti-ozonant chemicals added to counteract the effects of ageing, the weakening effect of the years is inevitable for all tyres.

FAQs

Is there a hard date to replace my tyres?

Tyres don’t have a single, set-in-stone expiry date. This is because there are so many factors that influence tyre lifespan: frequency of use, conditions of use, alignment and storage conditions if tyres are stowed at any point.

How can I check where my tyres were manufactured?

The place of manufacture of your tyre is specified in the tyre identification number, more commonly known as the DOT code. The first group of letters and numbers (usually two but sometimes three) following the letters DOT are the plant code. A quick internet search of the plant code will tell you the plant where your tyres were made.

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