The trailer goes on: from empty baseline to towing

Day three is the hinge of the trip. Everything before it was the control: two days and about 800 miles of empty Rivian R1T up I-15, holding right around 2 mi/kWh across the desert, dropping to 1.87 on the climb into Utah and touching 3.38 on the descent into Salt Lake. Clean baseline, no trailer.

The morning started with one last empty top-off at the Sandy Rivian Adventure Network, conveniently a hundred yards from the U-Haul depot. Trip A read 7,289.3. Then the enclosed U-Haul cargo trailer went on the hitch, Trip B got reset to zero, and the whole character of the trip changed. The first twenty miles run with the trailer empty; then the 2025 Ducati loads and it is a fully towed rig for the drive home.

Here is why this trailer is interesting. It is a U-Haul 5x8 enclosed cargo trailer, about 900 pounds empty, inside dimensions 8 feet 1 inch long by 4 feet 8 inches wide by 5 feet tall, rated to 1,800 pounds of load and 2,700 pounds combined. The Ducati and gear add roughly 400 pounds, so the whole trailer is only about 1,300 pounds, a fifth of the 6,000-pound Airstream. But a light trailer is not a low-drag trailer: an enclosed box presents a large flat front, somewhere around 28 square feet, so at highway speed the range hit comes mostly from pushing that air, not from the weight. That is exactly the variable a motorcycle on an open rail would hide, and it is what makes this a clean aerodynamics test against the empty baseline. The towed numbers start logging with the next dashboard.