i have the 255 55 18 nittos.. still get 320 to the tank.. there are alot of posts here for everything you are trying to figure out.. alot of how too's and just a great source of mods and information about your new fixation.. as far as the crown king trail goes.. the stair step towards the top was the hairiest part.. and I did have a spotter.. good luck and have fun
If you arent running all the time with the power light on.. try it.. it may increase your fuel mileage