Wheel Fitment
 

I was looking at the excel file for tire size speedo error in Larry III's locker. Could any one here modify the file to show additional information on wheel width? Or would the wheel width make much of a change?

i.e. 215/55/16 on a 7 inch 48 offset vs 215/55/16 on a 7.5 inch 40 offset.

I'm looking at fender clearance not speedo error.

I assume you got a handle on offset as that's a straight-forward number. Cross sectional width is not an exact science and could vary from brand to brand; however, the attached file (lifted from the Avon folks - credit where credit is due) lays out how to figure the numbers.