Trip #3. No mods, but slower speeds. OK, so it's a feeble attempt, but I' like to understand the relationship of speed and fuel consumption as it relates to pulling the trailer. Trip #3 was 189.6 miles on 14.1 gallons. 13.4 MPG. That's down 1.4 MPG from the baseline no trailer, and a 1.2 MPG better than the first trip with the trailer.
Interestingly, this is better fuel economy than with the gap filled.
The difference is speed. Don't have exact numbers, but the average speed on this trip was down something in the neighborhood of 10 mph from the first trip. Meaning, spending 20-25 minutes extra each way saved about the same in fuel as adding the gap filler inner tubes.
Of course, better aerodynamics makes more difference at higher speed, so the effect is diminishing, but with 3 people in the vehicle (that's an hour of man pay extra for the journey). Interesting balance to deal with on time v. savings v. cost.
I like the idea of time being irrelevant and just riding my bike. I'd have a hard time pulling said trailer, but aside from that, riding, even all day long, uses less gasoline than even the best of hybrids.
