In this Autos, Motorcycles & Planes video tutorial you will learn how to Read a tire sidewall. By understanding the information on the tire sidewall, you will come to know what is the tire size, speed rating and when it was manufactured. First look for a combination of letters and numbers. For example, P205/55R16 89V. 'P' implies passenger car tire. Some light trucks may also have 'P' or 'LT'. if there is no letter, the tire is designed to Euro standards. 205 is the overall width of the tire in millimeters. 55 is the height of the tire from the wheel to the tread. It is the aspect ratio of the sidewall height (113mm) and the tread width (205mm). in this case the height of the sidewall is 55% of 205mm. 'R' is for radial construction tire. 16 is the diameter of the wheel in inches. 89 is the tire's loading index. That is, how much the tire can carry when it is properly inflated. The larger the number, the more weight it can carry. The next letter is the speed rating. 'V' is designed for sustained speeds of 149mph. So, now you know how to read the tire sidewall.