A "C" indicates 6 plies, a "D" indicates 8 plies, and an "E" indicates 10 plies. The higher the number of plies in a tire, the stronger the tire is and the more air pressure the tire can safely hold. Higher ply tires require more air pressure to maintain proper wear. The number 185 is the tire's width in millimeters, from one sidewall to the other. The number 60 after the forward slash character means the tire's height from rim to tread is 60 percent of its width, which again is 185 millimeters. R14 means the tire is meant to fit on a 14-in. diameter wheel. Tire Size Guide: How to Read Tire Numbers and Letters Tire Class. The tire class is indicated at the beginning of the tire code. Typically, you'll see the letters P, LT, or Tire Width. The three-digit number following the tire class is the tire width. The width is the distance of the tire The aspect ratio, or profile, refers to the height of the sidewall as a % of the section width. In our example, 55 means the height is equal to 55% of the 195mm width. The bigger the aspect ratio, the bigger the sidewall will be. What Do the Numbers on a Tire's Size Mean? People often ask, "What do the numbers in a tire's size mean?" A friend of mine recently placed the following post on her Facebook wall: "Need some automotive help here. Will P225/60R16 tires fit a car that right now is 'wearing' LT215/70R16 tires?" The answers she got were as varied as could be. The most basic information that you'll find on a tire's sidewall is related to its size. This is normally written as 185/65R15, for example, though you'll sometimes see "P" (for passenger cars) The set of numbers straight after the tyre width refers to the thickness of the tyre wall (or aspect ratio), which is a percentage of the width. So, in this case, 55 would have a height equal to 55% of the tyre's width. This number is often referred to as the tyre profile. Tyre construction ogqZs8.

what does the size mean on a tire