I thought I was on top of things doing all the weight calculations and bought a truck and 5th wheel. I pick it up next weekend. I came to realize that I messed up as I only included the dry hitch weig...
Adding weight behind the wheels will lower the pin weight, but not as much as you would imagine. When I pulled a trailer behind my 5th wheel, I added about 600 lbs. to the rear and removed about 140 lbs. from the pin. And that weight was way off the back. You probably won't be adding any weight that far back, so the proportion will be even lower.
But it also depends on your wheelbase, distance of axles from the pin, spread between the axles, etc.