CarlLaFong wrote:I'm really amazed by the folks that have managed to defeat an empirical scientific fact. They have managed to get something for nothing. They should invent a perpetual motion machine next.
I think it is more complex than that. It is true that more weight and more rolling resistance equates to more gas, assuming all other things are equal. However, adding a trailer also significantly changes the aerodynamic profile of a vehicle, and at highway speeds, aerodynamics plays a larger role than weight. So, if the trailer actually improves airflow around the vehicle, the gain in aerodynamic efficiency can actually increase gas mileage more than the weight decreases it, resulting in a net gain in observed mpg. Or, it can break even. However, as you can see from the posts, it usually works out to be a net loss. It will vary for every vehicle/trailer combination.