Captain Bob
Supercharged
I do't know how you do it. Even riding carefully between 60-70 MPH I've never approached 40 MPG. Also, 215 divided by 5.8 equals 37.06 - pretty far from 40 (but better than I've ever done - city or highway).
How many miles I have left to go is not part of the equation. I was not ballparking on the 40 to 41 miles per gallon. That was manually calculated when I refilled the tank (several times). I calculate fuel mileage by dividing how many miles traveled (from a full tank) by how many gallons required to refill. The "miles left to go" is not accurate and should not be considered a factor when calculating fuel mileage. It is a datapoint however. If one day (after a fill up) it reads 215 miles left and another day it reads 160 miles left, I know fuel mileage has degraded. On my bike, you can safely add another 30 or so miles to the indicated "miles left to go" to get a more accurate reading of what's reality.