At present, my records are as follows (Note, my speedometer reads 10% high...Speeds referenced are corrected for actual speed of travel, so are 9% below what speedometer actually indicated):
Low: 40.87 MPG (75 MPH highway trip with strong headwind)
Average as of Today: 53.84 MPG
High: 61.11 MPG (4 consecutive days of commuting with no PLP, interstate, or short trips)
The commuting cycle used on this bike for these numbers was 17 miles 1 way, predominately 45 and 55 limits, ridden at those actual corrected-in-my-head speeds on mostly back roads with traffic control devices at about 2 out of 3 mile markers. The mix for the average is probably about 3:1 commuting vs. road trips.
On my bike, I'd start getting nervous around 150-160 miles of low-speed riding or 100-110 miles of high-speed riding. The one time I've gone to reserve and it wasn't by choice, the tank had been predominantly commuting and the trip odo showed about 168 when I pulled up to a stop sign where it died every time I let out the clutch to go, then I switched to reserve, rode to a station and filled up at 173.7 miles, getting 55 MPG flat on that tank.
Regarding speeds, my MPG seems to go down more quickly as speeds increase beyond about 55-60 (true).
As others have said, though, keep your own records and do your own math. There is a lot of variability between bikes, riders, and roads.
Last edited by IMBoring25; 09-11-2009 at 02:27 AM.