Yes I know that fuelly mileage is calculated. I was curious as to how far off reality the trip computer is.Look @ my signature. Like @mikefocke said, it's calculated. And yes, there is a 2-3MPG difference compatred to the BC. So the BC shows low 40's, calculated 39's over >6.500 miles (just under 11.000km).
Running Michelins allseason SUV tires, 2.5BAR on them. In The Netherlands most flat roads, around 30% highway @115km/h (about 70Mph), all other trips average 60-80 km/h (36-50 Mph).