The sidewall of a tire includes a variety of important information. The numbers and letters identify dimensions and performance standards that allow you to compare tires more accurately and efficiently. This diagram will help you to understand those numbers and letters. For assistance in selecting a replacement tire, always consult your Toyo Tires dealer.

 

Load Index
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The load index number and speed symbol correspond to the maximum load-carrying capacity of the tire and its maximum speed capability.

The load index number and speed symbol correspond to the maximum load-carrying capacity of the tire and its maximum speed capability.

The load index is an assigned number that corresponds with the load-carrying capacity of the tire. For example, "96" indicates a load-carrying capacity of 1565 lb at maximum inflation pressure. The load index for most passenger car tires ranges from 75-100.

Load Index Chart

Diameter
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The diameter indicates the size of the wheel from one side to the other.

The diameter indicates the size of the wheel from one side to the other.. You can learn more about changing the diameter of the wheels of your car in the Plus Sizing section.

 

Radial
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Tires with an "R" indicate radial tire construction.

The "R" stands for "radial," indicating the tire has radial construction.

Aspect Ratio
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The aspect ratio indicates the dimensional relationship of the section height to the section width.

The aspect ratio is the dimensional relationship of the section height to the section width. The lower the aspect ratio, the shorter the sidewall and the wider the shoulder-to-shoulder width.

 

Width
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The width indicates the widest point of a tire from sidewall to sidewall.

The width of a tire is referred to as its section width.  The width indicates the widest point of a tire from sidwall to sidewall.

The section height is not noted on the sidewall of a tire but it is also measured in millimeters. The section height is approximately the distance from the rim to the tread surface of the tire when it is not carrying any weight.

 

Tire Type
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Some tires have a P or LT in front of the tire width, identifying them for passenger or light truck use.

Tires with a “P” are for passenger car use. Some passenger car tires may not have a “P” and are considered hard-metric tires. Some light trucks and SUV’s are equipped with original equipment P-metric or hard-metric tires. Tires with a “LT” are for light truck or SUV use only.

Treadwear, Traction
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The UTQG code provides consumers with information on tire treadwear, traction, and operating temperature resistance.

Uniform Tire Quality Grading

The Uniform Tire Quality Grading System, or UTQG, is a system developed by the government designed to provide consumers with information on tire treadwear, traction, and operating temperature resistance. A number, followed by two to three letters, identifies the grade on the sidewall.

Treadwear Rating

The treadwear grade is a comparative numerical rating based on the wear rate of the tire when tested under controlled conditions on a specified government test course. For example, a tire graded 200 would wear twice as well on the course as a tire graded 100. The rating increases in 20-point increments. It is important to note that the true performance of a tire depends upon the actual conditions of its use. Actual conditions may depart significantly from the test conditions due to variations in driving habits, service practices and differences in road characteristics and climates.

Traction Rating

The traction rating indicates the tire's ability to stop a vehicle moving straight forward on wet pavement. The ratings are AA, A, B, and C, with AA being the best.

Temperature Rating

The temperature rating indicates the tire's ability to effectively dissipate heat. The ratings range from A to C, with A being the best.

Max Cold Inflation
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These numbers indicate the tire's maximum cold air pressure capacity along with the corresponding load limit.

These numbers indicate the tire’s maximum cold air pressure capacity along with the corresponding load limit. Never exceed the maximum cold inflation pressure for normal driving conditions.

U.S. DOT Safety
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This code indicates compliance with all safety standards established by the U.S. Department of Transportation and provides additional information about the tire manufacturer.

This code indicates compliance with all safety standards established by the U.S. Department of Transportation and provides additional information about the tire manufacturer.

The first two numbers or letters are the plant code where the tire was manufactured, and the last three to four numbers represent the week and year the tire was built.

Tires built in the 1990's will have three numbers and may have a triangle to note the decade. Examples are below.

Note: Recently it became mandatory to apply a partial DOT serial number on the sidewall opposite the complete DOT serial number. The partial DOT serial does not show the week and year that the tire was manufactured, but may still assist consumers in identifying tires should a recall be necessary. The purpose in applying the partial DOT serial number was to facilitate tire identification when the full DOT serial number may have been mounted towards the inboard side of the vehicle, and consequently not visible unless the vehicle was put on a lift for inspection.

Tires built since January 1, 2000

The last four digits, 3607, mean this tire was manufactured in the 36th week of 2007.

Tires built before 2000

The last three digits, 517, plus the triangle mean this tire was manufactured in the 51st week of 1997. In the absence of the decade triangle, this tire would have been made during the 51st week of 1987.

 

Load Index

The load index number and speed symbol correspond to the maximum load-carrying capacity of the tire and its maximum speed capability.

The load index is an assigned number that corresponds with the load-carrying capacity of the tire. For example, "96" indicates a load-carrying capacity of 1565 lb at maximum inflation pressure. The load index for most passenger car tires ranges from 75-100.

Load Index Chart

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Diameter

The diameter indicates the size of the wheel from one side to the other.. You can learn more about changing the diameter of the wheels of your car in the Plus Sizing section.

 

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Radial

The "R" stands for "radial," indicating the tire has radial construction.

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Aspect Ratio

The aspect ratio is the dimensional relationship of the section height to the section width. The lower the aspect ratio, the shorter the sidewall and the wider the shoulder-to-shoulder width.

 

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Width

The width of a tire is referred to as its section width.  The width indicates the widest point of a tire from sidwall to sidewall.

The section height is not noted on the sidewall of a tire but it is also measured in millimeters. The section height is approximately the distance from the rim to the tread surface of the tire when it is not carrying any weight.

 

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Tire Type

Tires with a “P” are for passenger car use. Some passenger car tires may not have a “P” and are considered hard-metric tires. Some light trucks and SUV’s are equipped with original equipment P-metric or hard-metric tires. Tires with a “LT” are for light truck or SUV use only.

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Treadwear, Traction

Uniform Tire Quality Grading

The Uniform Tire Quality Grading System, or UTQG, is a system developed by the government designed to provide consumers with information on tire treadwear, traction, and operating temperature resistance. A number, followed by two to three letters, identifies the grade on the sidewall.

Treadwear Rating

The treadwear grade is a comparative numerical rating based on the wear rate of the tire when tested under controlled conditions on a specified government test course. For example, a tire graded 200 would wear twice as well on the course as a tire graded 100. The rating increases in 20-point increments. It is important to note that the true performance of a tire depends upon the actual conditions of its use. Actual conditions may depart significantly from the test conditions due to variations in driving habits, service practices and differences in road characteristics and climates.

Traction Rating

The traction rating indicates the tire's ability to stop a vehicle moving straight forward on wet pavement. The ratings are AA, A, B, and C, with AA being the best.

Temperature Rating

The temperature rating indicates the tire's ability to effectively dissipate heat. The ratings range from A to C, with A being the best.

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Max Cold Inflation

These numbers indicate the tire’s maximum cold air pressure capacity along with the corresponding load limit. Never exceed the maximum cold inflation pressure for normal driving conditions.

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U.S. DOT Safety

This code indicates compliance with all safety standards established by the U.S. Department of Transportation and provides additional information about the tire manufacturer.

The first two numbers or letters are the plant code where the tire was manufactured, and the last three to four numbers represent the week and year the tire was built.

Tires built in the 1990's will have three numbers and may have a triangle to note the decade. Examples are below.

Note: Recently it became mandatory to apply a partial DOT serial number on the sidewall opposite the complete DOT serial number. The partial DOT serial does not show the week and year that the tire was manufactured, but may still assist consumers in identifying tires should a recall be necessary. The purpose in applying the partial DOT serial number was to facilitate tire identification when the full DOT serial number may have been mounted towards the inboard side of the vehicle, and consequently not visible unless the vehicle was put on a lift for inspection.

Tires built since January 1, 2000

The last four digits, 3607, mean this tire was manufactured in the 36th week of 2007.

Tires built before 2000

The last three digits, 517, plus the triangle mean this tire was manufactured in the 51st week of 1997. In the absence of the decade triangle, this tire would have been made during the 51st week of 1987.

 

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