I usually average about 13.5-14.2 mpg.We just recently to a trip to Orlando from Chicago.On the way down going through the mountains and a lot of cross winds I was able to get a little better than 18.5mpg.On the way back up I got 17.8 with a good head wind.And my average speed was 77mph. All of this with an 07 Lincoln Mark Lt.3:73 limited slip front and rear.Stock 18 inch tires.And a Leer cap on the back.