there are two tire sizing systems in use. The most common and
widely uses is called the ISO Metric system, which we refer to as ISO.
The other is the Light Truck Notation system or Light Truck High
Flotation system which we simply refer to here as LTN.
The ISO system typically has three parts to it: Tire width,
measured in millimeters; the Aspect Ratio, which is a percentage use to
calculate the height of the sidewall from the width; and the Rim
diameter (in inches).
Typical ISO tire sizes would be: 195/65R15 or 225/50 16
These are the sizes which are uses on most passenger cars, SUV's and some light trucks. There may, or may not be letters preceding the numbers such as P, LT, ST, or T, which indicate they type of vehicle or the use the tire was designed for. The letter "R" may be left off, but usually is present to indicate the tire is of Radial construction. This may be changed to "B" or "D" to mean Bias-Ply or Diagonal Cord construction.
In this system all tire widths are multiples of 5, and the aspect
ratios are also multiples of 5, so they will always end in a 5 or 0.
Other numbers or letters may be present on the tire following these but they do not refer to the tire size.
In order, they refer to
This tire size converter will help you to find the equivalent tire size in either the LTN or ISO system. For most people there isn't a great deal of practical value in this other than knowing what their tire size would be if it were using the other system, but for people who would like to see if they could find similar tires using the other sizing system, this will provide a start.
in mind that the results are the EQUIVALENT to the tire you enter, but
the size which is calculate may not actually exist. Use the result
as a starting point to find something which will be close to what you
currently have or need .
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