How to Read the Information on your Tires

Have you ever wondered what all that information on the side of your tires means?

1. Tire Size (in this example LT 235 / 85 R 16

a. The letters at the start of the tire size indicate the service type. In this example “LT” stands for Light Truck but there could be “P” which indicates the tire is primarily for Passenger Vehicles or a “T” indicates a Temporary Spare designed to be used until a flat tire can be repaired or replaced.

b. The first numbers indicate the width of the tire in millimeters. In the example above it would mean the tires are 235mm wide.

c. The second number indicates the sidewall height as a percentage. In this example the tire sidewall is 85% of the tire’s width.

d. The “R” indicates the tire is of radial construction.

e. The final number indicates the rim diameter measured in inches.

2. Mounting Direction – Not all tires have this feature but with directional tires it is important to know which way the tire should be placed. Directional tires have a specialized tread and are designed to roll in one direction.

3. Maximum Load and Pressure – Tires have a maximum load they can carry and a maximum pressure that they can hold. It is also a good idea to check your owners manual for information on the recommended tire pressure for every day driving.

4. Trade Name – This is the name that the manufacturer gives to the tire based on the tread pattern. Each tread patter is designed for a different purpose and it is essential to be able to distinguish the different tires.

5. Materials – Sometimes you will find details of what the tire is made of and how it is made listed on the sidewall.

6. DOT code – The DOT number code is used for safety standard certification and is used in case of a recall. The DOT Tire Identification Number must begin with the letters “DOT” followed by a series of characters (usually 10, 11, or 12 numbers, letters, or symbols). These characters identify the tire size and manufacturers specifications, as well as the manufacturing location and date the tire was manufactured (listed as week and year).

7. Load Index – This is usually found at the end of the tire size information (example: 235/85R18 102S). The numbers before the letter is what indicates the load rating. This code indicates the maximum load a tire can carry:

8. Speed Rating – The speed rating is identified by the letter following the load index code. This indicates the maximum permitted speed the tire can sustain for a 10-minute endurance without being in danger.

9. Country of Manufacturer - Details of where the tire was made will be listed on the tire sidewall

10. Tire Brand – The brand name of the manufacturer will be listed on the tire sidewall

11. Tire Wear Indicator – Some manufacturers include a tire wear indicator. The indicator is usually set at 1.6mm. Once the tire tread reaches the tire wear indictor it is time to replace the tires.