Do you mean you got 30 mpg at 80 mph ?????
Gra
on a return trip to the UK driving manily on motorway I averaged 30mpg for the entire journey. While on the motorways I tried to keep her at 80mph as much as possible but obviously there were smaller amounts of driving on other roads at lower speeds too but in fairness they were minimal.
Tyre pressures were ~36psi all round which can be a little harsh ridewise but I'll take the economy on a long trip like that. I was reasonably well loaded too. Weather was cool but dry with little in the way of winds.
I was pretty happy with that and that was in a manual which has a slightly lower top gear than the auto I think.
Dont get me wrong, I normally dont see 30mpg, its only on a long run (as you said) that I get the chance and I dont honestly think I'd see an instantanious 30mpg figure normally at 80mph . The only time I've seen 30mpg is on two trips to the UK where I did 500miles + each time.
Day to day its more like 25 to 27mpg which I dont think is too bad considering the weight. I know people driving similar size vehicles who have been saying for years that they get 40mpg average on longer runs, I dont believe them !
Theres another thing, one trip I had a roof box, the next trip I didnt. Both trips were similar miles, similar speeds, terrain & weight, both trips returned same economy. So I dont think my roof box make a blind bit of difference economy wise ! ........... carparks are a different matter.