Tire Type The letter "P" at the beginning of the "Tire Size" tells us the tire is a P-Metric tire, referring to tires intended for Passenger vehicles. The letters "LT," would indicate it was designed for light trucks.
Tire Width Tire width is measured in millimeters from sidewall to sidewall. The first three-digit number in the tire size refers to the tire width. For instance, in a size P185/60 R14 tire, the width is 185 millimeters.
Aspect Ratio The ratio of the height to width. For example, in a P185/60 R14 tire, the 60 means the height is equal to 60% of the tire's width. The bigger the aspect ratio, the taller the tire's sidewall.
Construction The letter "R" in a tire size stands for Radial, which means the layers run radially across the tire.
Wheel Diameter The size of the wheel the tire is intended to fit. A size P185/60 R14 tire is made for a 14" diameter wheel.