Tire Buying Guides

Understanding your tire's DOT code & its importance

A close up of a tire's sidewall, showing the DOT Code.
Last updated 11/03/2023 - Originally published 9/23/2020
Written by SimpleTire

The construction and sale of tires are far more complicated than the average person realizes. Tire technology has continually progressed to meet the demands of the ever-changing automotive industry, as well as other industries that incorporate the use of precisely matched tires for optimal vehicle function.

One thing that is necessary for all tire companies that plan to market and sell their products in a variety of world markets is proper coding. These codes are based on specific legal demands that are leveled by any number of governing bodies. In the United States, the code was developed and is governed by the Department of Transportation (DOT). This is known as the DOT code and is on tires legally sold in the United States of America with the exception of tires that aren’t intended for street use.

What is the DOT code?

The DOT code is something that's listed on every tire that's legally manufactured for sale in the United States of America for use on public roadways. You won’t find this on tire’s intended for racing, competition off-roading, farm equipment, etc.

This code is an alphanumeric code that can be seen on the sidewall of every tire. The DOT requires tire manufacturers to stamp the code on each and every tire. The reason for the DOT code is, first and foremost, vehicle safety. For example, the code helps with safety by making it possible to track sales. This information is used to target the owners of tires in the event of a tire recall.

Reading the DOT code

The DOT code has changed over the past three decades, allowing the system to evolve so that it's easier to read for consumers as well as retailers. The current coding system was put in place in the year 2000. At present, the DOT code begins with three letters: DOT. Those letters are followed by two alphanumeric symbols that represent the Plant code, or where the tire was manufactured.

The last three numbers represent the week and the year in which the tire was manufactured. For example, if the final four numbers read 1405, the tire was manufactured in the fourteenth week of 2005, or March '05.

This code varies slightly from decades prior when a three-digit code was used. In the 1980s the three-digit code represented the week of manufacturing, as well as the year manufactured within the specific decade. For example: If the last three digits were 017, the tire was manufactured in the first week of January in 1987.

The 1990s offered a slight change in the plan by adding the symbol of the triangle after the code. This triangle represents tires manufactured in the ‘90s.

The importance of the DOT code

As mentioned, the most significant reason for the DOT Code is tracking for safety purpose. Tire companies will be well aware of the codes offered to each of their tire models, making it easier to quickly inspect a line of tires that were ordered by automotive manufacturers or were recommended to hundreds of dealerships as OEM replacements.

The DOT code is also a very handy tool for consumers who are affected by a tire recall. With a simple check of the DOT code in the garage or driveway, one can quickly assess whether or not they may have faulty or potentially problematic tires on their vehicle.

Finally, the DOT code also serves as the stamp of approval on a tire from the United States Department of Transportation. Nearly every legally street-driven car in the U.S. will boast tires that possess this code, other than some classic cars, or cars purchased in and/or imported from Europe. European tires carry a similar code known as the E-code.

Vintage European Cars

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