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How to Read a Tire Sidewall

How to Read a Tire D.O.T. Code

The "DOT" symbol on commercial tires certifies the tire manufacturer's compliance with the U.S. Department of Transportation (DOT) National Highway Traffic Safety Administration (NHTSA) tire safety standards. The DOT serial number located on the inside sidewall near the rim. The letters “DOT” are followed by eight to thirteen letters and/or numbers that identify where the tire was manufactured, tire size and the manufacturer’s code, along with the week and year the tire was manufactured.

New Tire D.O.T. Code

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Where is the DOT code located on a Continental Tire?

1. Manufacturing Codes
DOT Manufacturing Code
  • Characters 1 & 2 = Manufacturer and Plant
  • Characters 3 & 4 = Tire Size Code
  • Characters 5/6/7 = Tire Type or Model

For example, this tire was manufactured in facility A3, which is the code for Continental’s Mount Vernon, Illinois, plant. Its tire size code is 72 and the tire type is KWU. This manufacturing code allows the reader to identify similar tires produced in the same plant.


Learn more about our Mount Vernon Tire Plant.

2. Department of Transportation
Department of Transportation
  • All tires used in U.S.A. must display a D.O.T. Number.
3. Date of Manufacturing
D.O.T-date of manufacturing image
  • Characters 4 & 5 = Week of Manufacture (01 – 53)

  • Characters 6 & 7 = Year of Manufacture (Last 2 Digits)

For example, this tire was manufactured in week 31 of year 2018.


You may be wondering why there are 53 possible weeks of manufacture, when there are only 52 weeks in the year. D.O.T. week numbers are calculated differently. In D.O.T. week numbers, the first full week of the calendar year is week one. Therefore, it is possible that the end of December will have a “week 53.”


Retread Tire D.O.T. Code Article

ContiTread Retread DOT Code
1. Manufacturing Retread Facility
Retread Manufacturing Codes


  • Characters 1 – 3 = Retread Facility

Tires that are retreaded must display the retread manufacturer’s D.O.T. code on the sidewall. This is often placed in the area reserved for branding, or near the tire’s original D.O.T. code. Each time a tire is retreaded, it must be branded with a new code.

2. Date of Manufacturing
dot retread-date of manufacturing
  • Characters 4 & 5 = Week of Manufacture (01 – 53)

  • Characters 6 & 7 = Year of Manufacture (Last 2 Digits)

Reading Tire Information