I believe the Ram Big Horn Off Road edition is the equivalent of what my 2013 Ram Outdoorsman was. They are the same truck except the Outdoorsman/Off Road gets 18" LT tires vs 20" P tires, minimally aggressive AT tires vs road, a bit stiffer shocks in the back and some skid plates. It actually increased payload/towing capacity, at least back in 2013. It is not a lifted, oversized tire rock crawling machine. It is for hunters that might drive through some fields to their blinds.
My trailer is a few feet shorter and lighter than the OPs. I never had sway problems with the Ram, but I also have a
Husky Centerline hitch that has the friction based sway control, not a sway bar. It is also a toy hauler which is tongue heavy (without a toy in the back) and I do have issues with porpoising if I am not careful on my weight management.
For my last trip with the Ram I had loaded the truck bed with firewood. It bounced horribly. Coming home it was fine, since all of the wood had been burned.
I switched to a new Silverado over the winter with slightly lower capacities. I could tell immediately when I pulled the camper from storage that my hitch needed to be adjusted. I raised the brackets on the trailer frame a notch and that took care of the rear end squat I was getting. I also bought a Sherline tongue weight scale since the dry tongue weight and rated tongue capacity on the truck were both 950 pounds.
My first test with the tongue weight gauge showed it was right at 950. Moving all my gear to the back dropped it to 850 and it rode better. I also tested it with a full fresh tank which didn't change the tongue weight - which makes sense since the tank is directly over the axles. I also moved another 30-40 pounds of gear from the basement storage at the nose to a tool box in the trailer. The only stuff I keep up front now are chocks, levelers and Lego blocks.
Pulling it home after the first trip did have a bit more porpoising. I'm guessing it was because my waste tanks (forward of the axle) were partially full, as was the water heater. I also pulled through a CAT scale and was within my specs on everything with about 1500 pounds of capacity on the trailer and much more on the truck.
I now know that to avoid porpoising.
- Empty the truck bed.
- Heavy gear to the back of the camper.
- Dump the waste at the campground.
- Drain the water heater.