how to read a dot number

How To Read A Tire’s DOT Number- Complete Guide 2023

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How to read a DOT number on a tire? Before that, you must know what a DOT number is. Don’t worry! You’ll find all the information you need in this article here.

You may be perplexed by the number and letter sequence on your tire sidewall if you are a novice driver. These specifications refer to the tire DOT code, which is critical for helping you specify important information about your tire.

If you look attentively, an etched DOT number may be seen on every tire. This number provides essential information about the tires that keep you safe. However, drivers are not always aware of what their DOT number means or how it is read. Here is a detailed explanation of how to interpret a tire’s DOT number.

What is A Tire DOT number?

DOT stands for the Department of Transportation National Highway Traffic Safety Administration, which the United States established in 1971. The “DOT” sign validates the tire manufacturer’s adherence to the NHTSA tire safety requirements set by the United States Department of Transportation (DOT). It confirms that the tire maker satisfies all of this organization’s safety guidelines.

The DOT serial number is found on the inside sidewall near the rim of tires manufactured in the United States. The initials “DOT” are followed by eight to thirteen letters and/or digits identifying the manufacturing location, tire size, and the manufacturer’s code, as well as the week and year of manufacture. After 2000, the extended number set became more generally known on all tires. This is the most popular and dependable method of reading your whole tire specifications, such as the time and location of manufacture.

How To Read a DOT number on a Tire?

how to read tire's dot code


Tire Date Codes are often called Tire Identification Numbers (TIN). Typically, the Department of Transportation provides up to 13 characters to advise you of important information about your tire manufacturer. How do you read the DOT tire codes on your tires? The answer is given below.

The Beginning: DOT

The letters DOT appear at the beginning of every tire identification number (Department of Transportation). It’s a symbol that confirms you’re obtaining tires that meet the Department of Transportation’s standards. It also serves as a clear, universal starting point for the TIN of a tire (tire identification number).

Tire Size Code

Your tire size code is the following two digits or letters. The tire size code is a little more complicated than the other markers. The National Highway Traffic Safety Administration (NHTSA) used to have a uniform list of tire sizes and the two-digit numbers that signified them. According to the U.S. Federal Register, the DOT allows manufacturers to choose their tire size code. This adjustment was made to make it easier for producers to create new tires without waiting for the NHTSA to update its code list. Unfortunately, this makes translating the tire size on your tire’s DOT number difficult. Fortunately, there is a more straightforward technique to determine your tire size.

  • 7-12 Character TIN

The first two characters stand for plant code, which the manufacturer assigns. The following one or two letters represent your tire’s size code.

The following code group has four characters. These are the internal codes through which the tire manufacturer specifies the specific construction for that tire. Depending on the manufacturer, these characters might have a maximum length of 12 characters. The remaining four characters belong to the date code and represent the manufacturing date. This reading applies to any tire manufactured since 2000.

  • 13 Character TIN

The first three characters of a 13-character TIN represent the plant code. The subsequent six letters indicate the tire’s size, kind, and other essential qualities. The final four numbers represent the date of production of the tire. As a result, the current DOT tire identification number has 13 digits.

Tire Manufacturer Characteristics

The third group of data represents the qualities of the manufacturer. It is primarily an area for manufacturers to convey tire differentiation or other brand-specific information. According to the U.S. Federal Register, “the third grouping may be utilized at the manufacturer’s discretion to convey any additional relevant tire characteristics.” The third grouping is unnecessary unless a tire is made for a brand name owner.” The National Highway Traffic Safety Administration is then notified of the manufacturer’s set of codes.

This grouping, like the tire size code, does not always give helpful information to drivers. It is commonly used for recalls, faults, and other formal identification purposes.

Tire Age

A tire may grow poorly without ever hitting the road because of its age. Tires begin to degrade thermo-oxidatively after five years of age. This chemical reaction can significantly influence tire safety on the road.

The last four digits of your DOT number will tell you how old the tire is. The first two digits in this cluster reflect the week of the year in which your tire was made. The last two digits reflect the year your tire was made. For example, if your tire’s last four DOT numbers are 3020, it was made in the 30th week of 2020.

How to check the tire manufacture date?

Some drivers may be perplexed about how to obtain a tire DOT number. If you are in the same scenario, here is a hint on how to read DOT numbers on tires that you may require.

Tires Manufactured Since 2000

Since 2000, four numbers have been utilized for the Date of Manufacture. The first two digits indicate the week, while the final two digits indicate the year of manufacturing. In the following example (DOT AF WD9E 0517), the number 05 denotes that the tire was manufactured in the fifth week of the year. The 17 indicates that it was made in 2017.

Since the year 2000, the date of production has included four digits. The first two numerals reflect the tire manufacture week, while the last two characters denote the production year.

Tires Manufactured Before 2000

Tire series numbers for manufacture dates before 2000 are three digits rather than four. The first two denote the manufacturing week, while the last alludes to the year.

Before the year 2000, the manufacturing date was represented by three numerals. The first two digits indicate the week, while the last digit indicates the year of manufacturing. A decade sign (a triangle on its side) is inserted at the end of the DOT serial number to identify tires made in the 90s.

Are Incomplete DOT Numbers Legal?

The partial DOT numbers determine the prevailing DOT standards, which require the whole number to be signed only on one tire sidewall. To put it another way, if you find certain characters on one sidewall, check the adjacent sidewall to obtain the whole DOT number.

When there is no DOT number on the sidewall, it implies that the tire does not meet all U.S. regulations. As a result, tires with missing DOT numbers are banned in the United States.

Final Words

Now that you know the mechanics of a Tire’s DOT number, you can do proper maintenance and not fall in trouble with the authorities. Do not buy tires that don’t have proper DOT codes.

If you want to take thorough care of your tires, you must also learn about their various aspects, such as Tire Pressure, Tire Rotation, Tire size, etc. That way, you can extend the life of your tires by a significant margin.

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