Re-posted from Tire forum:<P>After some analysis of the wheel and tire options for the S60, it appears that the <BR>diameters of each of the options is different enough to yield an almost 10mph delta from <BR>the smallest combination to the largest. I was wondering if anyone knows whether the <BR>speedo is recalibrated depending on which option is selected? If so, and aftermarket <BR>wheels are purchased, is it that easy to recalibrate the speedo later?