When you are in the market for new tires, it is important to know which tire out there is right for your vehicle. This information is written in code- tire code, and it is located on the sidewall of each tire. The markings on your tire sidewall contain a mix of letters and numbers, aka tire code. Knowing how to read the code will help you determine which tire you need. Here is a summary of the code.
- Tire Class – The first character in a P-Metric code is a letter and it represents the tire class:
- “P” Passenger
- “LT” Light Truck
- No letter means it is a European standard passenger tire
- Section Width – After the tire class, there is the 3-digit section width number. This is the measurement of the tire width from sidewall to sidewall in millimeters.
- Aspect Ratio – You will find the aspect ratio by looking for the two-digit number after the slash. This number refers to the sidewall height as a percentage of the section width.
- Tire Construction – This letter code is next and it describes the tire’s composition.
- “R” stands for radial construction. The tire’s plies run at 90 degrees to the centerline of the tread.
- “D” stands for diagonal bias construction. The plies are situated at angles lower than 90 degrees.
- Wheel Diameter – It determines the diameter of the wheel mount.
- Load Index – This number is next and it indicates how much weight your tire can carry at different inflation pressures.
- Speed rating – This is a letter indicating the maximum speed that a tire can safely reach and maintain that speed
- DOT – The DOT designation indicates that the tire meets or exceeds the U.S. Department of Transportation's safety requirements for on-road use.
- Plant Code – After the DOT, The Plant Code characters identify the tire’s manufacturer and site of creation.
- Tire Size - After the plant code, the tire size is a two-character a code determined by the manufacturer.
- Brand Characteristics – This is determined by the manufacturer as well, and like the plant code, tire size, and brand characteristics, it is intended for the manufacturer's internal use.
- Manufacture Week – The manufactured week identifies which week of the year in which the tire was made.
- Manufacture Year - The manufactured year identifies the year the tire was produced.
Although you may not need to know what each and every character in the tire code means, having a good understanding of the code can help you determine quickly which tires to consider for all your driving needs.