Got trailer sway? Add more towball mass. Oh, still swaying? Well, add more!
Here’s the problem with that advice. You can end up with a trailer that’s got an ‘ideal’ towball mass, whatever that is, and yet it is fundamentally unstable. And the reason is because you may have heavy weights at either end of the trailer. There’s a huge difference in towing stability between these two:
It’s entirely possible to have a trailer with a lighter towball mass be more stable that one with a higher towball mass, if the trailer with the lighter mass has the bulk of its weight located over the axles.
Some people grasp this intuitively, and good for them. They can go back to calculating moments and explaining the difference between momentum and inertia to lesser mortals. Or maybe just using my towing weights calculator.
For the vast majority of people to whom physics doesn’t come naturally I have, after reading lots of comments, made this video to explain. And not just because I found a way to have 48 bottles of beer and 2 bottles of wine written off against tax.
Don’t just hook up and hope.