[Padgett]

Bill is entirely correct, a WDH does not add or change any weight (other than that of the WDH itself) .

What it does is to add force vectors. Think to a bow. Strung or unstrung the weight is the same but a good English longbow takes a strong man to string and all of the force is within by the bow with an equal and opposite at each tip. A wound spring.

A WDH acts a lot like a strung bow. except the arm lengths are different so the effect on each end is different and translated to a rotating moment on both the TM (all on the single axle) and the TV (to unload the rear and load the front). Since the arm is shorter to the rear axle than the front of the TV, the effect is felt more at the rear and less at the front.

Now if the arms were straight then I would agree there would ne no anti-sway effect but they are not (the tongue forms an "A") and as the angle between the TV and TM changes, so will the force (why going over a bump can be interesting) so there will probably be some dampning effect but how much I cannot say.

Anyone who wants to discuss the physics involved can contact me offline, I imagine most lost interest at "force vectors".

ps this is all conjecture, I have never had a WDH (though my TM came with mounts).