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 Tire Size Meaning There are two ways that tire manufacturers display tire size, inches and metric. To find the tire size meaning in inches is very straight forward. Example A : 33X12.50R15 The first number is your overall diameter of the tire. In this example the tire diameter or "height" is 33 inches tall. 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. P denotes passenger-car tire. Some may start with an LT prefix, used on heavy-duty trucks. The number 235 is the cross-section width in millimeters, and 65 is the ratio of sidewall height to What Do The Numbers On Tires Mean? Tire service type ratings. Most tire sizes begin with one or more letters -- for example, P or LT. The letter tells us P = P-Metric (Example: P215/65R17 98T). P-Metric tires are the most common type of tire. The P stands for passenger Metric / Euro-Metric Tire Width The tire width is measured from sidewall to sidewall of the tire. It is represented by a three digit number and measured in millimeters. In our example above, the width is 185mm. Aspect Ratio Aspect ratio is the ratio of the height of the tire's cross-section to its width. Tyre size explained Tyre dimensions. Width: The section width of your tyre in millimetres, from the inner sidewall to the outer sidewall. Example: 195mm. Aspect Ratio: The height of your tyre from the base of the tread to the rim, as a percentage of the tread width. Low profile tyres have smaller aspect ratios. 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) LKfkk.

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