Wheel position on RV frame?

Please do not double post. See any new responses to your question here.

Some semi trailer can also slide the read axles forward or aft to adjust the amount of pin weight on the truck.

You will only find on GN horse haulers. This is because most of the weight of the horses will directly supported by the rear tires.

Semi-Truck has 2 sets of dully wheels so designed to carry 1/2 of a loaded trailer weight. Semi Trailer wheels at the back carry the other 1/2 of loaded trailer weight. Most semi trailers have 42,000# load plus weight of trailer. Now to relate to a common 5th wheel, the trailer and load ballpark 12,000 to as much as 18,000#. Trailer axles toward center = trailer wheels carrying majority of load. 3/4 ton pickups limited to about 2400# pin weight, dually 1 ton pick ups about 4500#. These are just ballpark numbers from memory to give you a idea of "apples / oranges" comparison.
Randu

Apples and oranges, Jack...................

Weight , semi tractors can carry the weight pickup trucks cannot,