On Friday, September 4, 2020 at 4:55:40 PM UTC-7, wrote:
There are a number of threads on RAS concerning vehicle size vs sway potential. The gist seems to focus on mass and wheelbase of the tow vehicle (more mass, longer wheelbase preferred), fore/aft loading of the trailer (10% of trailer weight on tongue), tire size/construction (radial vs. bias ply) and tire pressure for both the trailer and vehicle (higher pressure = stiffer sidewalls).

Of course, since this is RAS, assorted self proclaimed "engineers" will come out of the woodwork arguing the exact opposite of any of these principles. Using their logic, the "ideal" tow vehicle is a motorized skateboard with silly-putty tires and the ass end of the trailer loaded down. But with vortex generators. Please ignore these people.

Sometimes pictures are better than words as it is harder to argue with what you can see with your own eyes (assuming that you can still see, unlike Jonathan):
https://www.youtube.com/watch?v=-uvPIjaK01A
https://www.youtube.com/watch?v=iCDt4tjxp-E
https://www.youtube.com/watch?v=YjZn_zQt_Q0
https://www.youtube.com/watch?v=UdmlPu33Iew
The cause of many of these accidents is pretty obvious: tow vehicle too small, very bad trailer load distribution, and speed. Others are not obvious from the video. One thing that is common: the time period between initial instability and the crash is very short, a few seconds.

Tom