Tire Sizes And Tire Size Conversions

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About Tire Specs


Have you known about tires - an important part of your car? Hereunder is some information that you should know about it so that you can have your car be in best performance. One such specification is tire sizes and tire size conversions. Tire size and tire size conversions are one way to know how tires will fare when faced with various travel conditions.


  1. Size - This, of course, speaks of the size of the tire, and is usually seen on the sidewall. For the convenience of motorists, tire manufacturers have listed tire sizes by width, height and diameter.
  2. Temperature - This, on the other hand, indicates the tire's resistance to heat. It is usually represented by the letter A, B, or C, with A of course as the highest and C as the lowest.
  3. Traction - Traction describes the tire's capacity to respond to the vehicle brakes even when wet. Like temperature, it is also graded with letters, this time AA, A, B, and C, with A being the highest and C the lowest.
  4. Treadwear - Treadwear, meanwhile, is about the capacity of the tire to endure wear and tear in comparison to other tires. Normally, tire treadwear begins at 100; so, if a tire has a grading of 150 for treadwear, it means that the tire can last about 1.5 times longer than tires with a 100 grade.
About Tire Size and Tire Size Conversion

Right now, we'll be focusing more on how to deal with size and size conversion.


As mentioned a while ago, tire sizes are usually imprinted on the sidewall of the tire in a sort of format, with the width shown first, followed by the height of the entire sidewall, and then the diameter of the tire rim. Here is a representation of how tire size is specified on the sidewall:




For the width, of course, all we have to do is to get the measurement of the tire in terms of how wide it is, and it should be in millimeters.


The computation begins with the second element, the height. That is because the height is usually listed on the sidewall in percentage, and not in millimeters. So, if we want to get the exact tire height size conversion in terms of millimeters, all that needs to be done is to multiply the tire height, converted into decimal form, to the tire width. For example:


300 /60/ 20


This means that the height is 60% of the 300 mm width. In other words, we have a tire that has a height of 180 mm.


On the other hand, the diameter is usually designated in the sidewall in terms of inches. To convert to millimeters, the typical formula is as follows:




So, if, for example, we have a wheel that measures 406 mm, then we convert as follows:


180 mm x 2 = 360

360 + 406 = 766 mm


Meanwhile, here is another interesting fact about tire size conversion is the fact that one could also measure how far the tire can travel per revolution through the figures listed. This is also called the tire circumference. This is measured as follows:




If we will use our example, the tire circumference would be about 107.358 inches.

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Galih Prasetya has 13897 articles online and 13 fans

Galih Prasetya is a freelance article writers mostly on dimensions related topics. Before you spent your money to buy a set of new tires, check this Tire Size Comparison guide to make sure that you're buying the right one.

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Tire Sizes And Tire Size Conversions

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This article was published on 2010/09/13