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2 Inch 50#


Product Description

2 inch 50# welded type king pin for heavy duty Semi Trailer and truck Parts:

King pin (7)


Item No.

King Pin Size


Skid Plate Thickness

Fifth Wheel Size









50 ( 2" )





50 ( 2" )





50 ( 2" )





90 ( 3.5" )





90 ( 3.5" )


1. Production  :

King   pin for heavy duty semi trailer and tractor

Welded type king pin, bolted   type king pin.

2. Size of King pin:

2 inch, 3.5 inch, 50mm, 90mm, 50#, 90#

3. Application:

Trailer , semi trailer , truck , tractor,   container

4. Size of 5th wheel:

 2 inch, 3.5 inch,   50mm, 90mm, 50# ,90# .

5. Skid plate thickness:

8mm, 10mm, 12mm

6. D-value:

162KN, 240KN.

7. Reference brand:

JOST, WONDEE, FUWA brand kingpin

8. Color

Red, shinning black, dark black, grey,   blue, As requirement.

9. Warranty:

12 months since shipping date.

10. Related Certificate:

ISO9001; TS16949; COC; PVOC; CIQ; SONCAP;   BV; C/O; FORM E.

11. Lead time:

About 10~15 Working Days

King pin (1)

 What is the heavy duty steel KING PIN for semi trailer and truck?

The king pin is a very important connecting device between the tractor and the semi-trailer, and it is the most important safety equipment for a semi-trailer.

The King pin’s materials generally use carbon steel and alloy steel, mostly 40Cr round steel. The king pin is installed on the semi-trailer and connected with the 5th wheel installed on the tractor to form a trailer train to complete the towing work. The king pins are mainly used in trailers, trucks, semi-trailers, etc. The product installation and disassembly are simple, convenient and fast, which not only improves the universal type of king pin, but also improves work efficiency.

King pin (5)

Classification of King pin:

According to the shape, it can be divided into mushroom type, cross type, double spoon type, "l" type, etc.,

According to the different diameters of connect pin, the king pin can be divided into 50# and 90#, which is usually 2 inches and 3.5 inches king pin. 50# king pin is suitable for semi-trailers with a maximum total loading of less than or equal to 40 tons; 90# king pin is suitable for semi-trailers with a maximum loading of more than 40 tons and less than or equal to 100 tons.


According to different assembly methods, it can be divided into welded type king pin and bolted type king pin:

1. The bolted type king pin consists of a Bottom pallet, a center pin and 8 self-locking bolts. The thickness of the skateboard with 8mm, 10mm and 12mm.


When the bolted type king pin is worn out or accidentally damaged, it must be replaced. The method is: remove 8 self-locking bolts (self-locking bolts are for one-time use), tighten the new center pin with 8 self-locking bolts, and tighten the torque is 130Nm, and the bottom pallet is suitable for 2-inch and 3.5-inch center pin interchange.


2. The welded type king pin is to weld the king pin directly on the slide plate of the semi-trailer, so the King pin cannot be replaced. The material of this kind of traction pin is 20CrMnTi, and the surface is carburized and quenched to enhance the wear resistance of the surface. The thickness of the skateboard, welding type king pin are also available in 8mm, 10mm and 12mm.

King pin (2) 

Processing and production process of king pin:

King pin production follows the following procedures:

1) The choice of steel material. Generally, 40Cr, a clean low-alloy steel with stable chemical composition, is used as the material of choice for the king pin.

2) Forging. Cold forging is generally used. Pay attention to the precise deformation of the material during the forging process. Before and during forging, attention should be paid to dimensional inspection, magnetic inspection and macro-impregnation.

3) Product heat treatment and inspection.

King pin (6)

King pin's replacement:

As a safety part of a semi-trailer, it is very important for driving safety. When the key connection part of the king pin is worn to a certain degree, it needs to be replaced. After the semi-trailer runs 50,000 km, its dimensions must be checked regularly. The correct installation and operation of the 5th wheel and king pin can greatly extend the service life of the 5th wheel and king pin, and more importantly, ensure safe driving and reduce transportation costs. Improve transportation efficiency.


Mounting Instructions for King Pins:


The king pin connects the tractor with the semi-trailer and its safety is most important.


WONDEE king pins are manufactured to international standards which stipulate amongst other

requirements the length of the protruding king pin from the underside of the skid plate. Before the

king pin is mounted to the skid plate, check both thickness and flatness of the skid plate.

King pin (4)

 The skid plate must be adequately stiffened to take operational stress.


The king pin must be mounted centrally and at right angles to the skid plate. King pin of the bolted type must be protected against welding splashes during welding of the retention plate. After welding, fixing elements must be checked as to correct torque setting.

King pin with flanges must be correctly positioned and the securing nut must be tightened to the specified torque and secured with a split pin.

Before operating the semi-trailer, king pin must be amply greased with high pressure grease.

Sufficient greasing of king pin and fifth wheel coupling is most important for the lifetime of both



WONDEE supply various kinds of semi trailer king pin more than 20 years: 

King pin (3) 

In addition to supplying different types of semi trailer KING PIN, WONDEE also Supply different types of semi trailer components as below:

Wondee products collection



Xinhe Industrial Park, Xiamen, Fujian, China 361006





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