The kingpin acts as the key connecting component between the semi-trailer and tractor truck. Mounted on the front bolster of the trailer, it locks into the fifth wheel of the towing tractor to transmit traction force, brake force and bear vertical loads during transportation. Reliable kingpin performance directly determines driving safety for all types of semi trailers, including skeleton, lowbed, curtain side and tank trailers.

Our kingpins are forged from premium alloy steel and undergo strict quenching and tempering heat treatment. This manufacturing process greatly improves hardness, tensile strength and impact resistance, avoiding cracks or deformation under frequent heavy-load operation. We provide standard sizes including 2-inch (50.8mm) and 3.5-inch (88.9mm), which comply with international ISO standards to fit most tractor fifth wheels globally.

Two main installation types are available: welded kingpin and bolted detachable kingpin. The bolted version allows quick replacement once worn out, which reduces maintenance downtime and repair costs. Every finished kingpin will go through load and fatigue tests before leaving the factory. Anti-rust coating is applied to resist corrosion in wet, dusty or frigid working environments. Customized specifications and logo marking can be offered according to client demands. Featuring solid structure, high bearing capacity and long service life, our kingpins are essential spare parts for heavy-duty semi trailer projects.