Some of you may be interested in the data points for the 35d mpg while towing. The truth is that several of the higher mpg tankfuls include some towing of building materials, etc. for the 3 bay garage I'm building (see photo). But the lowest mpg tankfuls are almost exclusively towing.

All of our towing has been with our heavy duty 5x9 utility trailer w/ electric brakes rated at 5,000 lbs. It weighs about 1,500 lbs empty. A typical tow run includes hauling it empty to the quarry (OBC reads 20-21mpg) and hauling back a couple of tons of sand, gravel, road base etc. (OBC reads 15-18 mpg). Elevation en route ranges between 800-1,100 ft every few miles. I set the CC on 55 or 60mph (which ever is the speed limit). The 35d simply keeps on pulling regardless of the steepness on the hills. A typical weigh-in at the quarry is 6,540lb and weigh-out at 10,860 (net 2.16 tons). A 'towing tankful" includes some lower milage times like leaving the engine running to keep the A/C on in 105 degree heat during loading, hooking up the trailer, etc. And some better mpg segments like to/from the fuel station. So the overall average when towing has been somewhere between 18-21 mpg.

There are two mpg tankfuls that are pure towing (between 3,000-3,500 miles on the graph). We made a 300+mile trip towing our heavy duty 5x9 utility trailer. The mileage during that trip ran a little over 20 MPG. We filled it up when the left, when we got there and when we got home. Ironically the higher of the two MPG/Tanks is the trip back home where we were going up in elevation (sea level->1,100ft) and had a cast iron tub in the trailer.

Funf Dreisig

p.s. for scale the spherical water tank in the trailer holds 550 gal and is roughly 5' in diameter.

Attached Images