--- You put a scale on the ground directly under the TV's ball. You put a wood post between the scale and the ball just the right length to make contact. Now the scale just reads the weight of the post(lets say 10#s). Next you put the tongue of the TT onto the hitch ball. You look at the scale and now it reads 910#s. I assume you agree with me so far. --
This sounds like a trick question from a Statics 101 exam. The trick is that in order for a scale to measure a force, the scale must completely support that force. Therefore, if there is sufficient "slack" between the hitch head and the receiver so that the receiver does not "receive" any of the load, the scales would read 910#.
However, there is no point in continuing the analysis of your example because you have changed the support conditions. In addition to the TV's front and rear axles and the TT's axles, you have introduced the scales and post as an additional support. This changes the reactions which would occur when the WD bars are tensioned. I could attempt to explain what the new support loads would be under this unrealistic scenario, but I am afraid that would only further confuse the issue.
--- If this is true then you have to admit that the gravity weight between the tongue and the ground has lessened, which is why some say tongue weight has been redistributed or is less. Do you see that point of view??
The only "gravity weight" which enters into this analysis is the gravitational force resulting from the mass of the TT which is assumed to act at the TT's center of gravity. Since the center of gravity lies some distance ahead of the TT's fulcrum point, some of the gravitational force (weight) is supported by the axles and some by the ball coupler. The mass of the TT does not change or move. The reactive force at the ball coupler which supports some of the TT's weight does not change or move. The hitch load (vertical force between hitch head and receiver) will change because the WD hitch produces a net UP force on the hitch head.
If you want to define "tongue weight" as being equal to the hitch load, then you can say that "tongue weight has been redistributed or is less". I do not agree with that definition for tongue weight.
I don't think there are any more ways in which I can attempt to make my point.
Ron
