When I lifted my XK before Camp Commander this year and installed my new 33" tires, I found a significant drop in my MPG. I went from about 15 mpg to 10 mpg. (Based on mileage and speed from GPS data, not MPG calculator in the XK.) There were also some other mods that may have changed aerodynamics a little, skidplates changes, winches, extra weight in cargo, etc. I am guessing the majority of this change is due to the tires though.

How many of you have an extra set of road tires for use when traveling vs. just running the off-road tires? How much difference do you see in MPG or other factors? Have you seen it to be cost effective in increased tire wear?

What I am hoping to do is figure out how much MPG I might gain getting a second set of street tires, to see if it is cost effective in the long run.