How to Read a Tire Wall

The letters and numbers on tire walls can be decoded.

To the untrained eye, the letters and numbers on a tire wall may resemble an unfathomable hieroglyph. Learning to decipher this code will unlock important information that can help you choose the right tires for your vehicle.

Things You'll Need

• Charts listing tire load indexes and speed ratings

Instructions

1. Glance at the outer half to outer third of the tire sidewall. The tire manufacturer and the tire name are usually displayed prominently there.

2. In the same area of the tire wall, check for a separate series of letters and numbers that might hypothetically read: P215/65R15 89H
   P means the tire is meant for passenger vehicles. It is followed by the width of the tire in millimeters. Next is the tire's height-to-width ratio, followed by the letter R for radial construction and then the wheel diameter in inches. The final two numbers and letter set off from the series refer to the tire's load index and speed rating. Explanatory charts for this index and rating can be found online or at a tire store.

3. Look at the inner portion of the tire wall bordering the rim. Here is where you will find details about the tire's treadwear, traction and temperature grades. The treadwear grade has a baseline of 100, with higher numbers being better. Traction grades go from a best of AA to C. Temperature grades range from A, which is best, to C. The inner portion of the tire wall also has information regarding the ply composition and materials used, as well a tire identification number.

4. Pay particular attention to the tire's maximum cold inflation and load limits, which are listed on the inner portion of the tire wall by the rim. Refer to the inflation limit when checking the air pressure in your tires.

5. Write down the width, height-to-width ratio and wheel diameter of your vehicle's existing tires. Bringing this information along will make shopping for new tires much easier.

Tips & Warnings

• Shop around for bargains when buying new tires, but keep in mind that the cheapest tire may not be the safest or longest-lasting.

• Stay safe: Never exceed the speed grade or load index on your tires. For the greatest safety, keep tires properly inflated.

Resources

• Read this Article in Spanish
• Reading a Tire