For instance, my 77 has 245/60/15 tires, which have an OD of 26.57"
A 215/45/18 (making up a size) is 25.61"
What ever tire size you buy really needs to be +/-2% of your stock tire.
Thanks for the calculator. I think I'm good. My stock tires are actually 215/45/18. I was looking at a set of Dunlop Winter Sport 3Ds at 215/55/16, which comes to an OD of 25.31.
im running cooper zeon sport all seasons in the rear right now. it was getting to the point where i was stuck with only an inch on the ground with my 315's on the rear...