Changing the overall diameter of your tires will affect several aspects of your car. Tire Size Cal allows you to enter your current and any possible new tire sizes.
It will:
1. let you know your actual speed when your speedometer reads 60 mph
2. tell you how your ground clearance changes
3. tell you the difference in RPMs at 60 mph with the new tire size.
You can choose whether to do the calculations in inches or millimeters.
In addition to the calculations you can research new tires.