Harvard wrote:
Here is my theory about 4.5 Degrees:
"If the final RV build is nose level then the runtime caster will be about +4.5 degrees. These units are probably indifferent."
Sounds about right. I sit about 1" high in back (over 30') and have ~32% of my weight on the front axle with plenty of extra capacity on both axles.
Related note, I also own a 1998 E350 van. It used to be my tow vehicle in our TT days. I've long noticed that it handles way better with a load. Empty it sits stink bug and is a bit squirrely. Load up a few motorcycles and/or put the trailer on the back and it squats down a few inches and tracks way better on the freeway. Bet it's the caster change, right?