Trailer vs 5th Wheel Load

[alpo]

I probably over think things but is the Weight on the Hitch of a Travel Trailer and the Weight on the Pin of a 5th Wheel both the same when applied to the Vehicle’s Capacity. By that I mean the Weight on the Pin of a 5th Wheel is “Directly” (or damn close to) centered on the Rear Axle WHILE the Weight on the Hitch of a Travel Trailer is placing the Weight a good 4-5 feet rear of the Rear Axle. Using Geometry wouldn’t the Limits on a Travel Trailer be more Limiting AND induce lift on the Front of the Tow Vehicle? I realize the WD Hitch transfers Weight back toward the Front of the Tow Vehicle, but does it also eliminate the additional Weight being imposed by the Load being further back from Axle Center Line?

[JRTJH]

I'm no expert on this topic, but every (or almost every) vehicle manufacturer has a chart listing maximum trailer towing capacity for each vehicle. Typically, the fifth wheel maximum rating is several thousand pounds greater than the maximum conventional trailer rating.

I'm sure that the use of a weight distribution hitch has been factored into the maximum weight rating for conventional trailers. Part of that "adjustment" probably includes the location of the trailer tongue weight 4-5' behind the rear axle, as well as the weight distribution hitch "weight shift" with about 20% forward and aft, to the tow vehicle front axle as well as to the trailer axles.

So, the physics plays well with the geometry to provide the maximum weights in those charts....

Short answer: Yep your "head scratching" is already figured into the maximum weight ratings.... Those automotive engineers work overtime trying to keep up with the claims made by the marketing department who are trying to stay ahead of the competition....

[sourdough]

Originally Posted by alpo

I probably over think things but is the Weight on the Hitch of a Travel Trailer and the Weight on the Pin of a 5th Wheel both the same when applied to the Vehicle’s Capacity. By that I mean the Weight on the Pin of a 5th Wheel is “Directly” (or damn close to) centered on the Rear Axle WHILE the Weight on the Hitch of a Travel Trailer is placing the Weight a good 4-5 feet rear of the Rear Axle. Using Geometry wouldn’t the Limits on a Travel Trailer be more Limiting AND induce lift on the Front of the Tow Vehicle? I realize the WD Hitch transfers Weight back toward the Front of the Tow Vehicle, but does it also eliminate the additional Weight being imposed by the Load being further back from Axle Center Line?

I've read many explanations, theories etc. pertaining to your question. John summed it up about as well as you can. If you note on a truck there is a max conventional towing weight for the hitch then one with weight distribution. The 2nd number (with wdh) takes into account the redistribution of that weight you refer to that drops, even amplifies, on the rear axle without it. With the 5th wheel the only thing distributing the pin weight is the rear axle, tires and wheels...more or less.