Subject line pretty much says it all. Please cite cargo weight, driving habits, etc. Here're mine: Including luggage and me, I estimate cargo weight to be ~ 300lb, including a full-sized spare (17x7 wheel and 215/45x17 tire). My actual round trip average was 37.5 mpg over 6100 miles; the Garmin GPS' estimate was that my moving average was 70mpg. I set the cruise control for the speed limit +5mph at every opportunity (that is to say, in no traffic). (This mpg average includes the 5800' climb @77mph to Carlsbad Cavern on the return trip) I estimate most of my outbound driving thusly: MS to San Antonio: 630miles @75mph 39.5mpg San Antonio to El Paso: 441miles @85mph 37.5 mpg most of NM and AZ: 487 miles @80mph 39.25mpg Walnut Creek, CA to Los Angeles: 75mph* 39.8mpg *except for the Tehachapi climb (70mph). Since the return trip was by a circuituous route I don't intend to repeat, I didn't track exact destinations/fillups until the last tankful.
In the summer and spring, I had 205/17" on and I was getting 48 MPG average. I was getting 52 MPG with stock rim and tires.
