Tongue Weight Rating

LarryJM wrote:
Here is para 3.9 from the regulation you quoted excerpts from that I think are germane to your quote below and something I will refer to in my comments ....

"Primary Connecting System" means the combination of devices and their attaching structures that are normally utilized to maintain the connections between towing vehicles and trailer during towing operations. This includes, but is not limited to the ball-and-socket type of connection or draft means. NOTE: this does not include a safety chain, which is part of a secondary system normally utilized only upon failure of the primary connection, nor does it included weight distributing or sway control features or devices whose function is accessory to the maintenance of the towing vehicle-trailer connection

This seems to exclude all parts of either the WDH or Sway system such as the Sway bars, brackets, and sway hitch head.---

Larry, I think you completely missed the point of defining the "Primary Connecting System". Please note that the definition also refers to the "secondary system".

The Primary Connecting System is comprised of the components which are the path for transmission of the towing load between tow vehicle and trailer. These components are: "receiver" or "hitch", "shank" or "drawbar" or "hitch bar", "ball mount" or "ball platform", and "ball". The Secondary System primarily is the safety chains.

There is no reason to include "sway bars" or "brackets" in the definition of "primary connecting system" because those items are not part of the path for transmission of towing load.
I'm not sure what you mean by "sway hitch head", but I assume it is similar to "ball mount" or "ball platform".

LarryJM wrote:
---It would only include as mentioned in para 3.6 below that you quoted the ball and it's supporting structure which I take to mean the "drawbar" in it's simpliest configuration. I.E. these massive multiple height, extended length drawbars could be considered necessary to support the WDH functions to position the ball properly and not really what is being defined as part of what VESC is defining as the "Primary Connecting System"

Since a "drawbar", of any kind, is part of the towing load transmission path, it certainly would be included as part of the primary connecting system.
It is covered in the part of the VESC definition which says, "combination of devices and their attaching structures that are normally utilized to maintain the connections between towing vehicles and trailer during towing operations".

You are not correct in saying the primary connecting system would only include "the ball and it's supporting structure. Para 3.6 says:

3.6 "Hitch" defined for specific uses under Section 3.6(a. and b. below), generally means that part of the primary connecting system normally mounted on the towing vehicle, including a ball-support platform and those components which are attached to the towing vehicle.

Please note that this says, "including". It does not say, "only".

LarryJM wrote:
---Of course we have no way to resolve this issue of TW rating of the receiver when used in WDH configuration and how it applies to VESC-5 since it appears that VESC-5 sort of ignored all the WDH stuff which as already noted was almost non existent back when this reg was written and revised 36 years ago.

The WD bars and brackets were not included in the definition of "Primary Connecting System" because they are not part of the primary connecting system.

You are wrong about "WDH stuff" being "almost non existent back when this reg was written and revised". The authors of VESC-5 were well aware of that weight distributing systems were being used.
Please take a look at

10.2 Table 2 HITCH TEST FORCES

.
You will see that the right half of the table pertains to

WEIGHT DISTRIBUTING HITCH

Finally, please go back and read the portion of the definition of Primary Connecting System which states:

NOTE: this does not include a safety chain, which is part of a secondary system normally utilized only upon failure of the primary connection, nor does it included weight distributing or sway control features or devices whose function is accessory to the maintenance of the towing vehicle-trailer connection.

Yes, the VESC-5 authors were well aware of the existence of WDH stuff.

Ron