I took my 245-45-20 pzeros off today and had my 235-55-18 snow tires installed. I did the tire calculator to see what the difference would be, and it seems negligible, BUT the calculators say the new rpm based on size is about 716. falken's website says this tire has a 745 rpm. I can change the rpm in the xcal 3. I assume I should use the 745?
