How to Read Tire Ratings
Tires are much more than black, round and made of rubber. Thousands of different tire models are on the market today, each one designed to fit a specific type of vehicle and driving condition. Tire ratings systems exist to help you decide which tire is best for your driving needs. The best part is they're easy to find and understand.
Tire Ratings for Quality
The National Highway Traffic Safety Administration established a performance rating system based on three different performance categories. It's called the Uniform Tire Quality Grading (UTQG) system. A tire's UTQG rating is printed on the sidewall of many tire models. The markings look like this:
TREADWEAR 300 TRACTION AA TEMPERATURE A
A higher number means longer tread life under proper conditions. Tires can earn a rating of up to 800 in the UTQG system.
Ratings for the quality of traction provided by the tire are between AA and C with AA being the best.
The UTQG ratings for heat dissipation are between A and C with A being the best. This number rates how well a tire can deal with the heat that naturally builds up within while you drive the vehicle.
Maximum Load and Maximum Inflation
The maximum load and inflation indicate maximum capacity. It is not the recommended capacity. Always check your vehicle owner's manual for recommended load and inflation levels. These numbers are based on rigorous testing that determines the strength of the tires under extreme conditions. These tire ratings also appear on the sidewall of the tire. They look like this:
MAX LOAD 1433 LBS MAX INFLATION 36 PSI
The max load is the maximum load that can be carried at the tire's maximum inflation pressure. This is not the recommended load. Loading your tire to this level is dangerous. For your manufacturer's recommended load, check your owner's manual or the sticker in the driver's door jamb.
The max inflation is the maximum allowable inflation pressure. This is not the recommended inflation pressure for the tire when it is mounted on your vehicle. As with maximum load, it can be unsafe not paying attention to the recommended inflation. Check your vehicle owner's manual or driver's door jamb for the manufacturer's recommended inflation pressure.
If you see M + S (for mud and snow) molded into the side of your tire, it means the tire is graded by the Rubber Manufacturers Association (RMA) to handle tough weather conditions. M + S tires are not the same as winter tires. They are rated for muddy conditions and light snow only.
Winter Rating Symbol
Tires that include the mountain and snowflake symbol on their sidewalls are graded by the RMA to maintain traction and cut through water, ice, and snow in severe winter weather conditions. These tires are made of special compounds that remain pliable in temperatures that are consistently below 45 degrees Fahrenheit. Their special tread compounds stand up to more ice and snow when all-season tires may slip and slide.
The largest numbers you see on your sidewall rate the size of your tire. All sizing systems say two things about your tire:
- Section width: How wide the tire is across its tread
- Rim diameter: How big of a rim the tire fits
These two numbers tell you whether the tire will fit on your car.
The sizing assessment also gives a lot more information about your tire. Specs for how much load a tire can carry in a specific driving application and the speed a tire can safely drive are also included on your tire's sidewall.