The ride to and from the Black hills can be a real fuel burner. Run speeds of 80 mph and buck nasty head winds just makes the mpg go in the toilet. I can remember in 2008 making that ride on 2 wheels, caught some nasty head winds which made the mileage go from 40 mpg down to 28 mpg, this was on my -06 Ultra which at the time was 95". Every Harley in the group had their mileage tank badly, the lone Wing didn't get hit near as bad.