OK, I found this topic last night and it's kept me awake thinking about it. So here's my 2 cents worth.
First let me say I don't disagree in general with Ron or his calculations. But perhaps manufacturers should call them Weight Redistributing Hitches!
One interesting result of some of the calculations on the first couple of pages is that while the vertical load on the receiver was reduced by 300# (using Rons diagram), it was increased by the weight of the WDH (150# in some examples given there). So when compared to a setup without a WDH, the receiver only sees a decrease of 150# (From 650# without the WDH) to 500# (800# "hitch load" less the 300# "up force" from the bar leverage). I wanted to point this out so people don't over estimate their receivers capabilities with a WDH. (Or am I missing something here. My statics class was way to long ago and they've even changed the course number since then!)
The WD hitch does not redistribute any weights.
Weight distrubtion bars simply change where the tongue weight of the trailer gets applied to the ground. It does not change the tongue weight.
This is a very important point and really gets to the root of some of the problems debated here. Prior to being hooked together, there are typically four main bearing points on the ground: the TV front axle, TV rear axle, the tongue support, and the trailer axle(s). Once the trailer is hooked up, there are three (no tongue support). At that point, from the grounds point of view, the tongue weight has been distributed to the TV axles (of course the rear increases and the front decreases). Once the WDH bars are in place, the tongue weight (again from the grounds point of view) has been
redistributed between the TV axles and the TT axle(s).
Now of course it can be instructive to use examples of zero tongue weight and show that the WDH simply distributes the load from the TV rear axle to the TV front axle and TT axle(s) (and that is true), but the reason people who read this forum are interested in WDH is because a heavy tongue weight has overloaded the rear TV axle (and underloaded the front). While confusion can arise from someone who interprets "distributes tongue weight" to mean removes tongue weight, in practical real life situations, the load that is being removed from the rear axle by the WDH is being placed there primarily by the TT tongue weight.
When I was doing some additional research on this subject, I found an interesting definition on the Draw-Tite website:
"(W)eight distributing hitches apply leverage between the towing vehicle and trailer causing the TW to be carried by all axles of the tow vehicle and trailer. When TW is distributed in this way, trailers with greater TWs can be towed, resulting in a more level ride which reduces stress on the rear of the tow vehicle and provides greater steering and brake control." (TW=Tongue Weight)
This definition seems to me to be as good as anything else I've seen and hopefully doesn't cause confusion about decreasing tongue weight.
