downtheroad wrote:
The first defence against sway is:
a properly set up tongue weight and a balanced trailer....
True. But in an imperfect world, it's best to be prepared with a good hitch system that controls sway should it occur.
Even starting out with a properly set up tongue weight and a well balanced trailer doesn't mean it will stay that way while traveling.
Example: Starting out with a full tank of fresh water, consuming it along the way will redistribute a lot of weight from the fresh water tank to the black and grey tanks located in different areas of the TT. There goes a perfectly balanced set up.
Road conditions, weather conditions, and emergency maneuvers could also induce unexpected trailer sway, no matter the proper set up.