What do the tire size numbers represent

The P stands for PMetric. Its also measured in millimeters but may have different load capacity than a P or LT tire.

It is important that we understand tire geometry and be informed of the parameters that govern their performance.

What do the tire size numbers represent. Is the ratio of the height of the tires cross-section to its width. The two-digit number after the slash mark in a tire size is the aspect ratio. For example in a size P21565 R15 tire the 65 means that the height is equal to 65 of the tires width.

The bigger the aspect ratio the bigger the tires sidewall will be. Tire size specifications are outlined by the numbers and letters found on the sidewall of tires. It is important that we understand tire geometry and be informed of the parameters that govern their performance.

Tire sizes are defined by specifications such as the type width aspect ratio speed rating tire construction type and service description. 245 Section WidthTread mm 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.

C Commercial Example. 31x1050R15 C 109R Euro-Metric tire sizes ending with a C are commercial tires for use on delivery trucks and vans capable of carrying heavy loads. In addition to the C designation these sizes are also branded with a load range and service description rating load range B C or D.

Each group of numbers represents one dimension. The breakdown is as follows. The 235 grouping indicates the width of the tire from sidewall to sidewall in millimeters.

So in this example the tire is 235 millimeters 925 inches wide from sidewall to sidewall. If theres no letter before the first number you have a metric tire most commonly referred to as European size. Its also measured in millimeters but may have different load capacity than a P or LT tire.

TIRE WIDTH The three-digit number following the letter is the tires width from side to side looking at the tire head on in millimeters. Also called the section width this measurement is taken from outer sidewall to inner sidewall. These letters are followed by a sequence of 8-13 letters and numbers that denote that tires manufacturing location its specific size and the manufacturers identifying code.

The final four digits indicate the week of manufacture followed by the last two digits of the year of manufacture. The first number is your overall diameter of the tire. In this example the tire diameter or height is 33 inches tall.

The second number represents the width of the tire. In most cases with inch measurement tires the width will have a50 decimal after the initial number. Understanding Three Numbers in Tire Sizes The first number in a tires size say 225 is the width of the tire in millimeters.

This is pretty straight forward except that in the days of buying tires sized by the inch remember 311050x15 the first number was the height rather than the width. Back then it was inches not millimeters. In the size 25800-12 the meaning of the numbers is as follows.

25 - The overall height of the tire when mounted and inflated. 800 - The overall width of the tire when mounted and inflated. 12 - The diameter of the wheel this tire will mount to.

Tire diameter inches xxxyy1270zz where tire size is commonly written PxxxyyRzz on the sidewall. Note xxx is tread width in mm. Yy is aspect ratio sidewall height to tread width.

Zz is wheel diameter inches. The ISO Metric tire code consists of a string of letters and numbers as follows. A metric tractor tire sizes expression may look something like 52085R42 The 520 part means the tire is 520mm wide R means its a radial tire and 42 is the rim size expressed in inches just like the standard method.

That wasnt too hard but wait theres more. Tires with diameters 622 mm and 635 mm are both classified as 28-inch. Oddly enough tires with an inner diameter of 630 mm are classified as 27-inch.

These classifications originate from the time of tire brakes. In those days the exact outer diameter of the tire was defined by the brake. 1 These are some of the most important numbers on any tire as they tell you how big your tires are.

In this case the tire is 245 millimeters at its widest point when its mounted on a wheel of. The first number or second letter in a tire size represents the nominal width. Width is measured in a straight line from the furthest point on one sidewall across the tread to the furthest point on the opposite sidewall.

The following tire numbers represent rimwheel diameter measured from one side to another. The two-digit number is in inches and the most regular sizes are the following. 8 10 12 13 14 15 17 18 19 20 22 23 24 26 28.

You can see such tires on most passenger vehicles. This table represents Street Low Profile tire sizes most commonly used. The industry standard factory Golf Cart Tires that come on 99 of golf carts are 18x85-8 tiresMany cart owners decide to go with upgraded aftermarket wheels and tires in 10 12 and 14 sizes.

Which is where the hundreds of new tire sizesoptions come into play. And now here is a simple overview of how to read. P identifies your tire as a Passenger Tire.

The P stands for PMetric. If your tire size starts with LT rather than a P then it identifies the tire as a Light Truck tire. 225 identifies the tire section width which is the measurement of the tire from sidewall to sidewall in millimeters.