What size were the tires from the factory? I seem to recall 245 something, but can't recall the rest right now.

It's just simple math basically. For example, mine came stock with 235/75/15s. I now have 33s. That's roughly a 11% difference in height. So, my speedometer/odometer will be 11% off. And once I fill up, I take the mileage that's indicated on the odometer times it by 1.11 (adding the 11% to the miles already) and that gives me the actual miles. Then take the actual miles and divide them by the number of gallons used. That should give you the correct mpg. <img src="/forums/images/graemlins/kewl.gif" alt="" />

Richard <img src="/forums/images/graemlins/patriot.gif" alt="" />