Originally Posted by jmactootall
snip..... do they not make that rating considering the truck can handle the desired tongue weight?....snip
Vehicle manufactures establish a Payload Capacity based on a number of things, but a trailer's potential tongue weight isn't in the equation because the actual "loaded" tongue weight is an unknown. But yes, a trailer's loaded tongue weight is supported by the TV so it will be subtracted from the TV's payload capacity.
Where you will see a vehicle manufacture reference tongue weight is in the owners manual, and/or stamped on the OEM receiver......, but in both cases the actual tongue weight still has to be within vehicle weight limitations (GVWR, Payload Capacity, etc.)
The only way to determine a TV's tongue weight limitation, is to take the TV under loaded conditions (full fuel, passengers, cargo) and weigh it at a CAT scale (couple minute process, about $9). Subtract the CAT scale weight from the TV's GVWR noted on the driver's door...., the remaining weight (payload capacity) is what is available for the TT's loaded tongue weight, and the WDH weight (50lbs).
The vehicle manufacture will however establish a "published" Tow Rating for a specific vehicle, but this published Tow Rating is based on on very specific criteria: Base Curb Weight, 150lb driver, Full Fuel and fluids.
Good reference on Tow Ratings: http://www.jaycoowners.com/forums/f37/what-is-my-actual-tow-rating-3866.html
A vehicle manufacture doesn't assume one will use a WDH, it's up to the consumer to determine this based on the specified weight limitations established by the vehicle manufacture. Check your owners manual under the Towing section, most will have a statement about when using a WDH..., in most cases it will address a requirement of the TV's front suspension when using a WDH.
To truly determine if a WDH is adjusted properly and transferring the correct amount weight, a visit to a CAT scale is the only way to confirm this. Returning a TV's front suspension back to it's unhitched height via the WDH gets one in the ballpark, a CAT scale will allow you to dial it in. The CAT scale weigh-in will also provide all other weight data as well (loaded tongue weight, TT weight, TV gross weight, axle weights, etc.).
CAT scale how-to: http://www.jaycoowners.com/forums/f37/how-to-weigh-your-tv-tt-3871.html
Also, your RV dealership set-up your WDH under unloaded TV/TT conditions, the WDH should be re-adjusted under "loaded" TV/TT conditions to insure optimum TV handling of the TT, especially in less then ideal towing conditions.
Please feel free to ask for any clarifications.