A common towing myth is low tongue weight causes trailer instability, so you can “balance” weight at the rear of a trailer by adding mass to the front.
An oft-cited example is this video showing that moving a mass on a toy car on a treadmill with the front fixed to a stationary object makes it unstable.
Personally, I don’t drive on a treadmill going nowhere with the front of The Monster attached to a bar. But hey, it’s just a demo trying to illustrate a point. Unfortunately many people take away the wrong idea that light tongue weight is the primary cause of the instability. As documented on trailer stability, the weight distribution — moment of inertia in geek speak — is more important.
This video shows that equally balanced objects have different rotational stability depending on the shape.
In the case of our trailers, we want to be more like the spheres and the discs, not the hoops. The more weight in the center of the trailer, the better.
To be clear, I am not saying that adding weight to the rear of your trailer will make it unstable or that you should not drive with the tongue weight in the range specified by your owner’s manual. Stability is a continuum, and the most important factor is speed. Just be aware that more weight fore and aft is less stable than the same weight concentrated in the center if even the tongue weight is the same.