Realilistic mileage with a fifthwheel.

FWIW, since I'm running 265 tires instead of the OEM 245, my odo's off by 4%, which I recently rechecked over a 10 mile stretch of I-10. 10 miles by MP markers and only showed 9.6 miles, right at 4%. Every 100 miles I have to add 4 to get a "correct" mileage and it =does= make a difference. That said, my truck doesn't have the dash liar, but my 2 Hyundai cars do, and they're off anywhere from 1 to 2.5 mpg, in my experience. Only one instance on both cars have I had a hand-calc =less= than the dash and, maybe, 2-3 times each, where the mpg was < 0.5 mpg apart.

Lyle