To find out the size of your tires, you can check the sidewall of the tires currently fitted to your car. The size of a tire is printed onto the side of the tire, on the area known as the sidewall. The size is made up of a series of numbers and letters that indicate the width of the tire in millimeters, the height of the tire sidewall as a percentage of the width, the diameter of the tires inner rim in inches, the load rating of the tire, and the speed rating. For example, a tire with the code 205/55 R16 79T would have a tire width of 205 millimeters, a sidewall height of 55% of the width, a 16-inch inner rim size, a load rating of 79, and a speed rating of T. If you are unsure about the size of your tires, you can use a tire search tool by entering your vehicle registration number. You can also consult your vehicle handbook or the sticker that is usually found on the inside of the driver side door jamb.