dagosa: "It's about leverage and the entire length of he vehicle of a fwd works against the traction of a fwd car in an emergency maneuver when making sudden changes of direction."
Did I ever tell you the story about making emergency maneuvers while towing an RV with a 2002 Sienna? Perhaps I didn't, so I shall do so now.
I was driving to my grandmother's funeral in Illinois with my mother, her cousin, and my mother's dogs in the car, along with cargo, the RV in tow, and the proper weight distribution hitch with a sway control bar in use. We had just crossed from Georgia into Tennessee, I was in the right hand lane approaching an entrance ramp, and there was a little POS Dodge Omni parked on the shoulder with four people sitting in it. As we approached the Omni, without warning, the driver of the Omni pulled out directly in front of me, which to this day, I still don't understand. The driver had plenty of room to accelerate using the shoulder and the upcoming entrance ramp, so my only theory is that he was trying to kill himself and everyone else in the car deliberately. There was zero room for error. With a car to my left, my only option was to steer the minivan/RV combination onto the shoulder, drive around the Omni, and blare the horn in case anyone was approaching on the entrance ramp, so without jerking the wheel, I swung over to the shoulder and laid on the horn, swinging back into the lane once I was past the Omni. Because I had the proper weight distribution hitch and sway control bar, there was no tail-wagging-the-dog effect, in spite of the fact that I was making emergency maneuvers while traveling 64 MPH.
Yes, we can agree to disagree, but I speak from experience. I've seen and heard about plenty of minivans that were wagged into a ditch by a large trailer, but each time I asked, or bothered to look, the towing minivan had no weight distribution trailer hitch and no sway control bar, so it comes as no surprise to me at all that these drivers ended up in a ditch. Also, none of these minivans were towing pop-up campers. In each case, they were pulling full-sized trailers that were taller than the minivans and they had weights that were close to or above the manufacturers' towing capacities.
You cannot change the laws of physics, but you can, if you are willing to invest in the proper equipment and mind the manufacturers' weight capacities, use a minivan in the manner for which it was designed, and in a manner in which the engineers at Honda and Toyota say is perfectly safe.
Did I ever tell you the story about when I was driving that same rig, and had a tire blow-out on the trailer? Again, because I was using the proper equipment, there was no tail-wagging-the-dog effect, and the front tires had plenty of traction.
Living in our litigious nanny state, you would think Honda and Toyota would be setting their towing capacities lower than necessary, not the other way around.