JCL, it is a great link that you gave. I did not realize that car manufacturers go to that length to estimate the difference in the rotational speed of wheels on snowy roads. I bet it somehow factored into the ABS and traction control programs.

rh71, I run standard size tire for the 214 style wheels. They are Vredesteins, not OEM. So there could be a little discrepancy but not by much.