A tire's aspect ratio is its height to width in percentage. A tire with 205 mm width and 55 mm sidewall height has a 55% aspect ratio. Aspect ratio impacts tire diameter. The first number in a tire size is the width in millimeters, and the second represents the aspect ratio. Tire size can be defined as a collection of numbers and letters that describe tire type, width, sidewall height, and wheel diameter — alongside other information. An example of a common tire size is as follows: P225/65R17. The tire size for your vehicle and wheels can be found in two places: The sidewall of your tire. It is indicated by a letter of the alphabet, which refers to a table that is common to all manufacturers. Each letter corresponds to a certain maximum speed. It starts from letter "A", the only one which is broken down with numbers (A1, A2, A3, etc.) and which allows speeds of between 5 to 40 km/h. The section width is the width of the tire from one sidewall to the other measured in millimeters. In this example, the tire is 245 millimeters wide. 45 =Aspect Ratio (Ratio of Sidewall height to width) The aspect ratio refers to the height of the sidewall, and it is a percentage of the section width. Is the width of the tire 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 P215/65 R15 tire, the width is 215 millimeters. Aspect Ratio Is the ratio of the height of the tire's cross-section to its width. J - On some wheels, the letter 'J' might appear next to the wheel width, such as 16x7J. The letter J lets you know the shape of the wheels, and how the tire beads align with the wheels. J is commonly used for most passenger vehicles. Specialized vehicles may use other markings such as JJ, K, JK, B, P, A, D, S, T, or W. .

what does the size mean on a tire