How to choose the right tire
Here are some simple formulas to help you decide which tire size to use.
Here are the formulas with some examples:
1.Section width: To convert from millimeters to inches, multiply the given mm by .03937, For example the stock section width of a WS6 tire is 225 mm's So 225x.03937=8.86 inches. The section width is the widest point of the tire, not patch.
2. Section height: First you need to find sidewall height. This is done by dividing the section width by 25.4: 225/25.4=8.858 inches.
Then multiply the overall sidewall height by the aspect ratio: 8.858x.70=6.2 inches.
Then to get overall size multiply the sidewall height by 2 (top and bottom) and add rim diameter: 6.2x2+15"= 27.4 inches.
So let's plug in some others.
6.02x2+15=27.04 inches overall tire height.
Here is the 235/60 15 on my T/A
Here is the 255/60 15 on my T/A