Tires and Wheels information
Tire.exe is a DOS program that allows you do do the calculations yourself. Just remember to run it from a DOS prompt.
This page is for those of you that are upgrading or replacing your wheels and/or tires. These are probably the most popular and common sizes that are being used on people's cars. If you would like me to add information for a specific wheel/tire combo, please let me know.
The 1990 Subaru Legacy AWD recommends the 185/70R-14 wheels. Interestingly enough, the 2wd version only calls for 175/70R-14. This table has helped me figure out how to get the best performance and keep the speedometer the closest to stock as possible.
Some tire companies make their tires just a little bit larger or smaller than the specs on the sidewall. This is something to take into consideration. The tire pressure you are using can also change the height of the tire.
Formula for calculating sidewall height and overall height
Width * Aspect * .03937 * 2 + Wheel Diameter in inches.
I will use the 205/60R - 15 for an example. 205 is the width of the tire in millimeters. 60 is a percentage of the width of the tire in relationship to the sidewall height. Multiply 205 by .6 and you get 123. This is the sidewall height in millimeters. Multiply that by .03937 to get the sidewall height in inches. You must multiply this by two because there is sidewall on the top and bottom of the tire as measured by it's diameter. Now add the wheel diameter in inches and you should come up with 24.69, or something close. To convert this back to millimeters simply divide it by .03937.