A guide to the information written on tire sidewalls
Federal law dictates that tire manufacturers place standardized information on the sidewall of their tires. The information (letters and numbers) identifies and describes the basic characteristics of the tire and also provides a tire identification number for safety standard certification and in case of a recall.
We’ll use P215/65R15 95H M+S as an example and explain the meaning behind the tire’s labeling.
“P” indicates the tire is for a passenger car, while “LT” would be for a light truck and “N” would be for a spare tire. There are different designations depending on the application.
This is the width of the tire in millimeters from sidewall edge to sidewall edge. Typically, the larger the tire, the larger this number.
65 is the aspect ratio, which designates the tire’s ratio of height to width. Numbers of 70 or lower indicate a short sidewall for improved steering response and better overall handling on dry pavement.
“R” stands for radial, as in radial ply construction. This has been the industry standard for many years.
The rim diameter is 15 inches for this tire, meaning your replacement tire should also have a 15-inch diameter.
The number 95 designates the load index, which tells you how much weight each tire can support. This information is available in the owner’s guide. Not all tires may have a load index since this is not a requirement. In this case, the tire can support 1,521 lbs.
“H” is the speed rating, which denotes the speed at which a tire is designed to be driven for extended periods of time. The ratings range from 99 miles per hour (mph) to 186 mph. You may not find this information on all tires because it is not required by law. NOTE: You should not exceed the posted speed limits even if your tires have higher speed ratings.
Also shown as “M/S”, this indicates that the tire has some mud and snow capability. Most radial tires have these markings.