Here's a great method of weighing
one's small trailer using a bathroom scale and some leverage, posted by one of the Yahoo Scampers.
One change I would make is to call the Gross Weight
because my understanding is the Gross Weight
is only that weight on the axles (Tongue weight being on the tow vehicle), however that may differ between trailer manufacturers; I base my understanding on the fact that the trailer GVWR usually seems to be the same as the GAWR) -- Also, the distances should be measured from the center of the grease cap and there would be more accuracy if the small pivot piece on the left end of A was triangular
With larger trailers, one should be careful to keep A very long in order to not overload the scale.