Of course, starting with the advertised pin weight of prospective trailers PLUS cargo. Give or take, they can be off. Our rig has an advertised pin weight of 2950 lbs. But it actually weighted in loaded for a 3 night trip at 3400 lbs.
Each individual truck you look at will have a red yellow and white sticker on the door jamb showing the particular trucks actual payload. They can vary a lot from truck to truck especially in the Ford line-up because they offer so many variations of each model.
The payload of the truck includes all occupants, any cargo you place in the bed or cab of the truck, and the weight of the fifth wheel hitch. Some of them are 300 lbs.
Add all that up and deduct that from the payload of the truck and that's what you need.
I went to a dually from a 3500 srw for safety as the above formula was putting me right at the trucks payload. A lot of that sometimes is due to the tires on the truck. Good luck.
