When to Replace a Trailer King Pin Based on DOT Regulations

Updated 06/22/2020 | Published 08/15/2018

Question:

what is the fed regulation number for the specs you give on wear specs for the trailer king pin?????

asked by: James B

Expert Reply:

The Fifth Wheel Trailer King Pin # 337KP20050 is 2 inches diameter where the jaws of the 5th wheel hitch will connect. Typically the max wear on a king pin is .080 of an inch with a minimum diameter of 1.920 before manufacturers recommend replacement. DOT says the max wear is .125 of an inch with a minimum diameter of 1.875.

I did not find any specs for non-commercial trailer king pin requirements from the Federal Government. You can find all the federal information for commercial motor vehicles on the government site for the Federal Motor Carrier Safety Administration.

expert reply by: Jason S