Fuel mileage 5th wheel vs travel trailer

Totally different results than OP. My mileage went up when I switched back to a travel trailer of nearly the same size. Maybe I "wanted" it to be that way and drove a little more conservatively? Maybe the OP's TT had a dragging brake or some other mechanical problem? Maybe the OP's tow vehicle developed a problem after the switch? On the other hand, if 5ers now get 30-40% better fuel mileage, I may purchase another.

A brother delivered trailers around the country and told me he got better mpg with a 5er than a TT. Same truck with many different trailers and destinations

I would consider that quite an anomaly! Generally the higher frontal area above the tow vehicle is responsible for fuel mileage differences!

My opinion may be skewed by the tow vehicle (pick up truck) having a topper, which may have positively affected the air flow across the tow behind camper.

On a slightly different issue, unless extreme, weights are not a significant issue pertaining to mpg. If the same unit is used in a comparison, wind resistance due to increased speed is much more of a factor in mpg than is a few hundred to a thousand pounds of carry weight. Many folks will not fill their fresh tanks prior to travel. I would dare to suggest that under identical situations, the difference in fuel mileage is near immeasurable!

memtb

rhagfo wrote:
The total package is less aerodynamic, the 5er has smoother air flow than a PU and TT.

This ^^. There is much less of a gap between the cab and the front cap of a fifth wheel than between the cab and the front of a travel trailer. The longer distance with the TT setup allows turbulence to set up in the bed of the truck (coming over the cab) and air to slam into the front of the TT. On the fiver setup, the air flows more smoothly from the top of the cab up and over the front cap of the fiver.

Rob

Yep. Mileage is more about wind than weight.

The total package is less aerodynamic, the 5er has smoother air flow than a PU and TT.

“My thought is the weight distribution and pulling of hitches?”

IMO neither is a factor worthy of mention regarding MPG.