I run 30's and the diffrence is only 5 kph, i have a gps so I can compare the diffrence. Since the spedo has a 5% error rate anyways, the 5 kph caused by the bigger tires is not a real issue for me, well not a big enough issue for me to plunk down more $$$$ on another gadget!


08' Jeep Wrangler
64' Plymouth Sport Fury 383
58' Triumph TR-3A