guy I just found the coolest thing. After montes of searcdhing internet and manually using pencil,paper and tape measurement I found this it is an illistrator for wheels and tires. For an old guy like me this is the best thing since Coca Cola.... all you do is enter the information at the top on rims you are considering and the tires you are thinking about and shizam. I double checked ti again my stock rims and tire and it is right on the money.
http://www.bigcustomwheels.com/rt_specs.jsp