So far I've averaged 12.5 unloaded for 4000 miles.

Towed my mustang to the track last weekend. Trailer and car = 5000, plus carog and passengers is about 1000 more.
-- 10.0x MPG towing it there (240 miles) in 90 deg heat with a/c, stop and go traffic on the 215 through LA for 5 hours, do the math and I averaged 48 MPH. Not bad I thought for the heat and stop and go traffic.

Then it got better...... yes better
Returned home Sunday evening
-- 11.0x MPG towing it home (240 miles) in 75 deg temps without running the a/c and traffic flowing all the way home at 75 MPH.

All caluclations using the miles divided by the gallons since I don't have the built in calculator (instrument package).

Kevin, 05 250 SD, V10, 4x2, 4.10, CC, Torqueshift towing the #63 CMC Mustang

 

That's pretty good mileage. I get 12 empty with mine. Lower loaded, and even lower loaded and pedal to the metal.

What you really get the medal for is doing that 5 hr drive thru LA. Whew!

'05 F-350, V-10, 4x4, 6 spd, 4.30 LS, 18" rubber