not to belabor your point, BUT.... your forgetting that though the car and trailor may indeed weigh around 6000lbs if not more or slightly less, the rolling resistance is only very minimal. for example, lets say you have just a car that weighs 3500lbs on a paved road and all 4 tires are aired up, it would only take about 245 lbs of pressure to move it. sorry im not trying to be rude, i promise.