I experienced true trailer sway only once in all my years of driving (48 years now???)
It was a Chevy Lumina mini van pulling a Starcraft Venture Pop-up camper. We just had a rear hitch installed on the pop-up and had 4 bicycles hanging off the back. The first time out after installing the hitch, I got up to about 40 mph and the trailer started gyrating back and forth violently. I really did not feel it, but I sure saw it in the rear mirrors. I don't sit and focus on the mirrors, but they are always in my vision and any movement always catches my attention. The pop-up gyrating back and forth was insane. I really thought the trailer was going to flip.
Did I actually "feel" anything while driving. No, not really.
I slowed down immediately and got the trailer under control. The trailer had no brakes as it was under 3000 pounds (not required in Indiana). I then tried increasing my speed again, and again, and again. Every time at about 40 mph it started gyrating, almost bouncing from one wheel to another.
I get my laughs out of those YouTube videos that attempt to show what trailer sway is by the driver swirving left then right very vast, showing the trailer wiggle back and forth. THAT IS NOT SWAY. That is a controlled wiggle!
Sway is totally uncontrollable, and it acts like nothing you could ever force yourself to occur.
How did I proceed on that trip? We took the bicycles, but since we were camping close to home, I simply drove slightly under 40 mph so the trailer was in 100% control.
I've never experienced anything even closely remote to this experience with any of my 3 travel trailers. But then again, I've always towed with 3500 duly's too!
