there won't be a noticeable difference in the speedo/odo readings as long as you don't go from 15's to 16's - in the range of 27-30" will be close enough to factory, which I think is about 28.5" - 205/75R/15 to 225/85R will be about right, but all car sized radials are wider tread [fatter] than original - I got some 700R15LT Yokohama's that have a great look and proper height/width - didn't change the speedo noticeably from the 225/75R I had before
Bill
