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How to Read a Tire

A brief summary of how to read the markings on the sidewall of your tire.
The sidewall of your tire contains all the information needed to understand everything about that specific tire. All tires are required to have this information, regardless of the manufacturer brand name.

Tire Type - This term defines the intended use of the tire. P designates a passenger car tire and if the tire has a "LT" rating, then the tire would be for a light truck application.

Tire Width - This term defines the width of the tire measured in millimeters from sidewall to sidewall. Standard sized tires common if the off-roading industry are measured in inches.

Aspect Ratio - This term defines the the ratio of the height of the tire's cross-section to its width. For example, a 45 rating would mean that the height is equal to 45% of the tire's width.

Construction - This term tells you how the tire was manufactured.

  • "R" indicates a Radial tire.  This means the body ply cords run radially across the tire from bead to bead.
  • "B" indicates a Bias Ply tire. This means the body ply cords run diagonally across the tire from bead to bead.
  • See Article: Tire Terminology

Wheel Diameter - This term defines the width of the wheel that the tire is intended to mount with.

Load Index - This term defines the number that corresponds to the maximum load (in pounds of kilograms) that a tire will support when properly inflated.

Speed Rating - This term defines the number that corresponds to the maximum speed of the specific tire. Example: A "V" rating indicates that the tire has a maximum speed of 149 mph.

DOT - This term shows that the tire is compliant with all applicable safety standards established by the U.S. Department of Transportation (DOT). On the tire, this is always followed by the tire identification or serial number.  Generally this is a combination of numbers and letters with up to 12 digits.

UTQG - This term stands for Uniform Tire Quality Grading.  It is a quality rating system developed and used by the Department of Transportation (DOT) for safety standards.

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