How To Read a Tire Sidewall

The markings on a tire’s sidewall provide a lot of information about the tire. Knowing how to read your sidewall can save you time and help you make an informed purchase.

Tire Sidewall

Tire Width The three-digit number refers to the overall width of the tire in millimeters. A wider tire will out-corner a slimmer one.		Radial The letter “R” indicates a radial construction of the carcass plies. The carcass plies run across the tire from lip to lip, helping to provide strength, stability, flexibility, and ride comfort.
Aspect Ratio The relationship between the tire height and width. In this example, the tire height is approximately 60% of the tire width.		Wheel Diameter The number indicates that this tire fits on a wheel with a 16-inch diameter.
Load Index The load index can range from 0 to 279 and indicates how much weight the tire is certified to carry at maximum inflation pressure. Never buy a tire with a lower load index than your vehicle’s original tire.		Speed Rating* The speed rating tells you the top speed at which the tire can operate. Speed ratings range from N (lowest) to Z (highest) with one exception: the H rating falls between U and V. To maintain the speed capabililty of a vehicle, use replacement tires with ratings equal or greater than those of the original tires.
Mud & Snow The letters M and S indicate that this tire meets the Rubber Manufacturer’s Association’s standards for a mud and snow tire. The letters can be found in the following combinations: M+S, M/S, and M&S. All-season tires carry this mark.		Traction Tires are tested for braking on wet concrete and wet asphalt. If a tire brakes well on both surfaces, it receives an A rating. If it brakes well on one surface, it receives a B; and if it brakes poorly on both surfaces, it gets a C. AA is the highest attainable grade.
Severe Snow Symbol A severe snow marking appears on winter tires that are designated for severe snow applications.		Temperature Heavy loads, under-inflation, and high speeds can raise the temperature of a tire dramatically. An A rating means the tire resists heat damage well, B is not as good, and C means the tire passes the minimum safety standards.
Treadwear The government standard for wear is 100. If a tire has a rating of 200, we expect it to last twice as long. Conversely, a treadwear rating of 50 means it has half the mileage life.

Tips:
• Never choose a tire that is smaller than the tire that came with the car.
• If you are interested in a size other than your vehicle’s original equipment, or are upgrading, consult your local Phillips Tire store.