Product Introduction
The fifth-wheel kingpin is a critical load-bearing component connecting the semi-trailer to the tractor unit, serving to transmit traction and support the load. Forged from high-strength alloy steel and strengthened through heat treatment, the product offers excellent wear and impact resistance alongside a high safety factor.
It is available in two mainstream specifications-Type 50 and Type 90-and comes in two structural designs: integrated and assembled. The integrated version is formed as a single piece, offering exceptional durability and suitability for continuous heavy-duty operations. The assembled version utilizes a flanged bolt mounting system, allowing for easy installation and removal; individual components can be replaced after wear, thereby reducing maintenance costs.
Manufactured in strict accordance with industry standards, every unit undergoes load testing prior to shipment. These kingpins are compatible with a wide range of semi-trailers, including those used for general freight and oversized heavy-duty transport; custom specifications are available, and a stable supply is guaranteed.
Product Types
1. By Specification
- Type 50 (2-inch): Lightweight; commonly used on standard freight semi-trailers; suitable for light to medium loads.
- Type 90 (3.5-inch): Heavy-duty model; high load-bearing capacity; the preferred choice for trailers transporting oversized or heavy cargo.
2. By Structure
- Integrated Kingpin: Forged as a single piece; robust structure; impact-resistant; suitable for long-term heavy-duty operations.
- Assembled (Removable) Kingpin: Secured via a bolted flange; allows for individual replacement of worn parts; lower maintenance costs; widely used in the market.
Specifications
| Type 50 (2-inch) Kingpin | Standard diameter: 50.8 mm; compatible with 2-inch fifth-wheel couplings. Common mounting plate thicknesses: 30 mm/32 mm. Rated load capacity: approx. 50 tons; commonly used for standard-load general freight semi-trailers. |
| Type 90 (3.5-inch) Kingpin | Standard diameter: 89 mm; compatible with 3.5-inch heavy-duty fifth-wheel couplings. Common mounting plate thicknesses: 36 mm/40 mm. Rated load capacity: 90 tons; suitable for trailers used in oversized and heavy-haul transport. |
| Material | 42CrMo/40Cr alloy steel; integrally forged and heat-treated (quenched and tempered). |
| Mounting method | Integrated welding or bolted flange assembly. |
| Standard | GB/T 25607 (National Standard for Semi-trailer Kingpins). |
Product Features and Advantages
1. High-Strength Material for Safe, Stable Load-Bearing
Forged from premium 42CrMo alloy steel and treated with high-temperature quenching and tempering, the product boasts high density and excellent toughness. It effectively prevents breakage, deformation, or bending under heavy loads. Resistant to impact and tensile stress, it is perfectly suited for long-haul transport and rough road conditions, significantly enhancing driving safety.
2. Wear-Resistant and Durable for a Long Service Life
The contact surface of the kingpin undergoes precision machining and hardening, resulting in a smooth, wear-resistant finish. It resists severe wear and loosening even under conditions involving frequent towing and steering friction. With a service life double that of standard carbon steel parts, it eliminates the hassle of frequent replacements.
3. Two Specifications to Fit All Trailer Types
Available in the two mainstream market specifications-Type 50 (standard load) and Type 90 (heavy load)-covering light, medium, and heavy-duty semi-trailers. Whether for general cargo transport or heavy-haul operations, these pins offer a precise fit and exceptional versatility.
4. Two Structural Options for Hassle-Free Maintenance
1. Integrated Kingpin: Features a seamless, one-piece design for maximum structural strength and ultra-stable load-bearing performance. Ideal for long-term, high-intensity heavy-load operations with a very low failure rate.
2. Bolted (Modular) Kingpin: Designed with removable flange bolts, eliminating the need to cut the trailer frame. Individual parts can be replaced when worn without replacing the entire base, significantly reducing maintenance costs and downtime.
5. Precision Craftsmanship for a Stable Ride
Manufactured in strict accordance with national standards, ensuring precise dimensions and high concentricity. It engages tightly with the fifth wheel, preventing wobbling or drifting during transit. Responsive braking and steering, combined with reduced vehicle body vibration, significantly enhance overall driving stability.
6. Rigorous Quality Control for Reliable Quality
All finished products undergo load testing and flaw detection to eliminate defects such as sand holes, cracks, and cold welds, ensuring guaranteed quality upon delivery. We maintain ample stock and a comprehensive range of specifications; custom manufacturing is also available to meet diverse needs for trailer modification, repair, and replacement.
We specialize in the manufacture of various trailer chassis components, integrating R&D, production, sales, and after-sales service. Our core product range includes kingpins, trailer axles, suspension systems, landing gear, leaf springs, and towing devices.
Our facility is equipped with comprehensive forging, heat-treatment, and testing machinery. Every product undergoes rigorous quality control, ensuring robust materials and high load-bearing capacity. We offer a full range of specifications, support customization, and ensure a stable supply. Our products are compatible with various semi-trailers-ranging from standard cargo haulers to heavy-duty transport vehicles-and serve trailer manufacturers, the aftermarket repair sector, and international clients. Committed to quality and integrity, we serve the transportation industry by providing cost-effective products backed by excellent after-sales support.
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