Truck Sags from Trailer Tongue Weight with Round Bar Weight Distribution Hitch

Question:

I recently purchased a newerinch 2016 F150 4x4 extended cab XL 3.55 rear end with the 1.7 ecoboost engine.Previously I pulled my 27foot trailer with my trusty 97 F150. The problem I am encountering is setting up the weight distribution hitch for the newer truck. To begin with my older truck sits up 2inch higher unhitched than my newer one with the same size tires and rims. When I set the ball height and hook up the distribution bars at the minimum 5 links, the trailer is level but the truck 3inch in the rear and front s about 1. On the older truck it only ped about 1 1/2. If I raise the draw bar another hole increasing the ball height, the trailer height without the distribution bars is already to high on the nose of the trailer. 3inch seems like a lot of sag. The trailers dry weight is 4900 lbs and loaded maybe 6000 lbs. The center of the trailers axles is 10foot from the rear putting the tongue weight at approximately 750-800 lbs tongue weight. The distribution hitch is a round bar rated at 8,000-10,000 lbs, 800-1000 lbs tongue weight. Suggestions? would overload spring or airbags solve the problem? As far as I can tell I have set the hitch up correctly. Help, I would like to go camping before the summer ends.

asked by: Bob D

Expert Reply:

It sounds to me that you may simply have a weight distribution system that is not rated high enough for the tongue weight (TW) of the loaded trailer. Since your truck is a recent model year, I would not expect there to be an issue with its suspension. It is simple enough to measure the fully loaded trailer tongue weight using scale # e99044.

Also keep in mind that if there is any cargo in the bed that sits behind the rear axle, such as a generator or big loaded cooler, this cargo weight needs to be added to the trailer's own actual tongue weight to give you the total effective TW.

The ideal situation is that this total TW falls right in the middle of the system's operating range. If your actual total TW were to be 800-lbs, then you would want to be using a WD hitch rated for 600 to 1000-lbs so that your total is in the middle of its effective range.

The Reese trunnion bar system you referenced # RP66022 has an effective TW range of 600 to 1200-lbs so it would be ideal for a total TW of 800 to 900-lbs. If your system is rated for up to 800-lbs and that is your actual total TW then you may want to swap out your spring bars for a new set rated to handle more weight. I linked our page for replacement round spring bars below.

I also linked our page for replacement shanks in case you want to select a new one. You can use any brand of shank since they are use standardized hole sizes and hole spacing. For instance you could use a Curt shank like # C17123 with a Reese WD head.