Maybe I'm missing something here. Pin weights are about 20% on average of the trailers weight. They can vary some depending upon model and how it's loaded. I tend to run around 22% pin weight. If the pin weight is to light the trailer will porpoise and give you a bad ride.
If your trying to figure out how heavy of a trailer for your truck, figure out how much pin weight you can stick in the bed of that truck and using the 25% rule of thumb figure out your gross trailer weight. That will give a conservative idea. The hitch for your 5er will weight around 300#.
5er's will max out the load capacity of the truck before you will exceed the tow capacity of the truck. You need to weight your truck full of fuel and people like you are going on a trip and weight it on a CAT Scale (guess 7,500#). Subtract that from the GVWR on the door sticker of you truck (10,000# if my research is correct) and that's the pin weight you can handle. A 2,500# pin weight (25%) is a 10,000# trailer. Look at the 5r's GVWR not its dry weight as that is useless. The individual trailers empty pin weight and dry weight will give you an idea of its 5 pin weight ratio or percentage but once you load up the "basement" and/or other cabinets that will change.
2014 Ford SpecsFord says 12,500# but your pin weight will probably limit getting to this number. 12,500# times 20% is a 2,500# pin weight. Don't forget the wife, kids, dogs, hitch and everything else you need for the trip that goes in the truck limits pin weight. Air bags improve ride not capacity.
Good luck.
