We recently purchased a 16” HiLo, towed it from PA to CO with a 2006 Honda Ridgeline (5k tow capacity).

My unloaded MPG on a cruise like that is about 20-22 mpg.

Towing a conventional 17’ box camper I get 12mpg, and feel every passing vehicle and breeze.

The Hilo we ranged from 16 to 18, on cruise at 60-65mph. Best part was big rigs passing us at 80 mph and we never felt a thing.

Having towed a number of conventional boxes, you can really feel the drag when you hit about 45mph. The hilo feels the same up to cruising speed - just a load, not a sudden wall at 45.

2006 Tundra Double Cab SR5 4.7 liter V8
Hi-Lo Towlite 2206T
Ultragauge OBDII Scantool for real time monitoring of MPG, Trans & Engine temps, etc.

Took it on a 1700 mile round trip. Got about 13.5 MPG on average across multiple tanks of gas. I drove between 55 & 65. Played with speeds during that trip since it was the maiden voyage. Looks like 45MPH is the sweet spot for maximum MPG, 16 - 20MPG. That's a big range as I was only monitoring real time MPG over short distances. The difference between 45MPH and 60MPH is all aerodynamics.

Conversely, I rented a 22ft Coleman before I purchased the Hi-Lo and my MPG was about 11.3 mpg on a shorter trip.