Most trucks I have seen set up for a goose neck trailer has a 2-5/8" ball mounted in the bed. Someone left the ball up on our work truck today and I notice the "ball" on it is more like the kingpin on a semi trailer. What is the difference (besides the obvious), which is better, and which is more common?

 

Standard gooseneck ball is 2-5/16.

Big, heavy trailers sometimes have 3" ball.

Also, I have known a few around here to have 3" necks put on their trailers to deter free-loading neighbors from borrowing the trailer.

Actually, the genuine Gooseneck Brand hitch is not a ball at all. They have a pivoting ring made in the plate that goes in the truck bed, and the neck drops over this ring with a pin going through both to keep it all together.

Another type that was plentiful a few years ago is the Tri-Star that has a swiveling triangle plate made on the bottom of the trailer neck that mates with a channel on the plate that is in the truck bed with a bar sliding behind the plate to lock them together. Nobody could borrow these either.

 

Also, some actually have a trailer king-pin mounted upside down on the truck with an upside down fifth-wheel on the front of the trailer.

There are several of these around here.