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 s ...[more]
Driving around on underinflated tires is just a bad idea all the way around. Underinflated tires increase a car’s rolling resistance, meaning a drop in fuel efficiency since it takes more energy to move the vehicle down the road.
A single tire that’s down by ten pounds of air means a 3.3 percent drop in fuel economy…multiply that by all four tires, and you can figure on giving up ten percent of your gas mileage. The added friction and rolling resistance also means more heat is generated, and heat is the enemy of the internal structure of a tire. That heat will damage a tire to the point of failure. Studies show that underinflated tires are a full 25 percent more likely to fail, and at least half of one-car accidents involve a tire problem as a factor. And still, it’s estimated ...[more]