I had to do a series of Interstate runs here in ND a couple of months ago so I decided to test mileage out and see what happenend at different speeds. The first trip was to Dickinson, ND. About a 180 round trip. Filled up before I left and immediately upon return. No load, cruise set at 75, 16 MPG. Next trip was to Jamestown, ND. Same everything including fill-up station except this time ran 65 on the cruise control. This trip was about 180 miles and at 65, got 19 MPG. Third trip was to Minot, ND. This trip was about 200 miles. No load, cruise set at 55, same station fill-up as the two previous runs. At 55 I got 24 MPG. Actually just shy of 25 (I don't have my notes in front of me. ) Went camping over Memorial Day. Four hour drive from Bismarck to Canadian border. Had a 35 MPH headwind so I locked out the O/D and got 9 MPG at 65 MPH. The trip home had no wind and ran 65 getting 11 MPG with O/D engaged. When hauling the race car on a 20' open hauler (5000 lbs) I get about 13. Anyhow, the short of it was there was a big difference between 55 and 75 in MPG. I don't see me spending a whole lot of time running around the country side at 55 MPH. I could do 65 though and get almost 20 MPG so..... Winds are usually a problem here in NoDak Land and that plays havoc with speed and trailering. Just my 2 cents.