What is the King Pin Diameter on the Bulldog Gooseneck to 5th Wheel Hitch Adapter

Updated 10/19/2011 | Published 10/18/2011

Products Featured in This Question

Gooseneck to 5th Wheel Trailer Coupler Adapter - Inner Tube - Round - 25K lbs

(853)

$177.45

Question:

I am wanting to pull my gooseneck trailer with my semi tractor. Is the kingpin dimentions correct for a semi fifth wheel?

asked by: Jim S

Expert Reply:

The standard king pin dimension for a semi-trailer is 2 inches diameter, where the fifth-wheel jaw wraps around the king pin. I went out to the etrailer.com semi-trailer on our lot, see link, and produced a short video showing both of the king pins in close proximity to each other for you to see.

The king pin on the Bulldog Gooseneck-to-5th-Wheel Trailer Coupler Adapter, # BD0289580300, is an industry standard 2 inch king pin and will work in a semi-tractor fifth-wheel hitch, as long as the height adjustment is adequate for towing the trailer.

If your gooseneck trailer already has a 4 inch inner diameter tube welded on the tongue and a removable gooseneck hitch, you could use the Gooseneck to Fifth Wheel Trailer Adapter, # KPG5-R25-IP, on your trailer.

expert reply by: Robert G