A Brief History of the Tire
Ever wonder what the designations stamped on your tire sidewall actually mean? We’d like to break it down for you.
Let’s take for instance, “P195/60R15 87S”. This is a full service description of a tire.
In this case, “87S” denotes a tire’s load capacity and speed rating. The higher the number, the greater the load capacity – an 87 load capacity means that tire can support 1,201 pounds. Speed ratings range from L (75 mph) through V (149 mph), and an S speed rating means the tire is good for 112 mph. W, Y, and Z-speed rated tires are available for extreme performance cars and are rated as high as 186 mph.
As for the rest of the information:
--“P” denotes Passenger Tire
--195 is the tire’s width from sidewall to sidewall... in millimeters
--60 is the aspect ratio... the proportion of the height of the tire cross-section as compared to the width of the tread area
--“R” stands for Radial construction
--15 is the wheel size... in inches
There’s other information on the sidewall of a tire, such as its Mountain & Snow rating (if applicable), date of manufacture code and maximum allowable pressure. For the average consumer though, it’s good to know the meaning of the service description so you can be an informed tire buyer when it’s time to replace them. Remember, your vehicle was designed for a very specific tire size, and it’s best to stay with that size when you go shopping for new tires!