Metric tire size meaning

If there are no letters at the beginning it refers to the Euro-metric drafted by ETRTO. For example in a size P21565 R15 tire the 65 means that the height is equal to 65 of the tires width.

In example B this reads 285mm.

Metric tire size meaning. Finding the tire size meaning in metric measurements is a little more difficult and usually take a calculator to get exactly right. 30570R17 On metric tires the first number is your width of the tire in millimeters. In example B this reads 305mm.

There are 254 mm in one inch. 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 sizes will often start with letters.

For example P LT T and ST. When we use tire type P or P-Metric it means that the tire is made according to certain standards of the United States drafted by TRA for passenger vehicles. If there are no letters at the beginning it refers to the Euro-metric drafted by ETRTO.

Metric or Euro-metric sized tires are the ones without the P at the beginning such as 185R14 or the 22560R16 listed above. Using metric dimensions to reflect a tires width actually began in Europe in the late 60s. 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.

On metric tires the first number is your width of the tire in millimeters. In example B this reads 285mm. There are 254 mm in one inch.

To convert 285mm to inches you divide 285 by 254 to get 1122. 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. P designates this tire as a passenger car tire an LT before the tire size would mean the tire is a light truck tire and a European metric tire would have no letter before the tire size. 245 Section WidthTread mm The section width is the width of the tire from one sidewall to the other measured in millimeters.

There are two major size designations commonly used for passenger car tires called P-metric and Metric sizing. If you see a P in front of the tire size displayed on a tires sidewall it is a. Metric and Inch Tires Sizes While standard SAE tire sizes are easy to understand a 35x1250-16 tire runs 35 inches tall by 125 inches wide for a 16 inch wheel many popular tires particularly those under 35 tall use harder to visualize metric dimensions a 31575R16 tire is 315 mm wide with a sidewall height that is 75 of the width for a 16 inch wheel.

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 smaller number means a lower profile and the height-to-width ratio is shown as a percent.

For example if the aspect ratio is 90 that means that your tires cross-sectional height is 90 of its width. If the tire has the metric alpha or low-profile inch numbering system the aspect ratio will appear immediately after the width. Tire sizes that have a p in front of the numbers in the size description or no letter at all are p-metric.

If there is an LT in front of the size then it is an LT tire. Which tire type is right for you depends on how you use your vehicle. P-metric Tires for More Mileage and a Smoother Ride.

Metric Size Expression 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. The vast majority of tires manufactured and sold today come with metric sizing.

The tire size we will use for our example is a 12070ZR-17TL. It can also be written as 12070Zx17TL or 12070ZR17TL. Some manufacturers put the speed rating at the end of the size and do not indicate if the tire is tubeless or not.

In this case you will have a set of number in this manner. This Shinko tire reading means it is 100 mm wide with a 90 aspect ratio and can be mounted on to a rim of 19 inches. In short Metric measurement takes either the Widthaspect ratio-rim size format or Widthaspect ratio-speed rating-Tire Construction-Rim size format.

An alphanumeric designation such as MT90 17 represents the same tire size as 13090 17. Its just expressed in a different way. M means the tire is for motorcycle use T is the tire width code 90 is the aspect ratio and 17 is the rim diameter.

Tire Size Conversion Charts. Sidewall aspect ratio or section height is the ratio of the tire height and width that will tell you the tires section height. The two digit number that follows the section width ST175 80 -R13 LRD is the aspect ratio.

To find the section height you take 80 of 175 which is 140 millimeters so the section height is 140 millimeters.