Container Shipping
Container loading of Kales semi trailer for export, ensuring secure fastening and space optimization.
Factory DirectParts
Semi-Trailer King Pin 50 mm and 90 mm
Quick answer: choose the 50 mm king pin for standard semi-trailer use up to 40 tons gross weight, and choose the 90 mm king pin for heavier-duty trailers above 40 tons and up to 100 tons. If your fleet needs stable trailer-to-tractor connection service, this family gives you the right connection size without moving into a more complex coupling system than the route really needs.
Trailer Type
Semi trailer
Axles
Multi-axle options
Payload
Configured to project requirement
Semi-trailer king pin family: this Kales page covers the 50 mm and 90 mm king pin options used on standard and heavy-duty semi-trailer coupling systems. It is built for buyers who need a reliable replacement part with the right mounting style, surface durability, and fifth wheel compatibility for different trailer weight classes.
Engineering guidance from the Kales Vehicle parts team for buyers comparing king pins, fifth wheel couplings, and other trailer connection hardware across fleet rebuild and replacement programs.
Technical Snapshot
| Product type | Semi-trailer king pin family |
|---|---|
| Main sizes | 50 mm (No.50) and 90 mm (No.90) |
| Application range | Standard semi-trailers and heavy-duty semi-trailers |
| Material | High-strength alloy steel |
| Manufacturing method | Cold forging |
| Standards | GB/T 4606-2006 / ISO 337:1981 and GB/T 4607-2006 / ISO 4086:2001 |
| Mounting styles | Welded and assembled options |
| Shape options | Mushroom, cross, double-spoon, and L-shape variants |
| Price structure | Aggregate pricing around USD 10 to USD 25 depending on model and mounting detail |
Family comparison table
| Model | Use case | Gross weight guidance | Material detail |
|---|---|---|---|
| No.50 | Standard semi-trailer king pin | Up to 40 tons | High-strength alloy steel, cold forged |
| No.90 | Heavy-duty semi-trailer king pin | Over 40 tons and up to 100 tons | 90 mm chromium alloy diameter for stronger durability |
Best Fit Operating Profile
This king pin family is best suited to trailer builders, workshops, and fleet maintenance teams that need dependable tractor-trailer connection hardware for either standard-duty or heavy-duty semi-trailer service. It fits replacement programs, rebuild programs, and export fleet standardization work where the connection point must match the trailer weight class exactly.
Best for
- Standard semi-trailers that need a 50 mm king pin
- Heavy-duty semi-trailers that need a 90 mm king pin
- Trailer rebuild workshops standardizing coupling hardware
- Export parts buyers who need a known king pin size with clear weight guidance
Not ideal for
- Buyers looking for landing gear instead of a king pin
- Trailer programs that need the fifth wheel coupling unit rather than the king pin itself
- Applications where the trailer connection standard is not 50 mm or 90 mm
Why Buyers Choose This King Pin Family
- Two clear size choices: 50 mm for standard service and 90 mm for heavier-duty use keeps selection simple.
- Cold-forged alloy steel: built for wear resistance, corrosion resistance, and long service life.
- Standard-compliant production: aligned to GB/T and ISO references used for reliable trailer coupling hardware.
- Mounting flexibility: welded and assembled options make it easier to match different trailer programs.
- Shape variety: mushroom, cross, double-spoon, and L-shape variants support different production and fitting preferences.
- Range-price structure: practical for parts buyers who need the right king pin specification rather than one fixed stock number.
How This King Pin Family Should Be Evaluated
The correct way to assess a semi-trailer king pin is not by price alone. Buyers should verify gross trailer weight, coupling standard, fifth wheel compatibility, mounting method, and whether the trailer is a standard-duty or heavy-duty application. That is the difference between ordering the right part and ordering a connection point that creates service problems later.
| Buyer situation | Best-fit Kales option | Why |
|---|---|---|
| Standard semi-trailer coupling up to 40 tons gross weight | 50 mm king pin | Matches the lighter-duty trailer connection class |
| Heavy-duty semi-trailer above 40 tons and up to 100 tons | 90 mm king pin | Built for stronger connection demand and heavier trailer service |
| Fleet rebuild that needs trailer connection hardware plus coupling unit | Fifth wheel coupling product page | Better fit when the buyer needs the tractor-side coupling device too |
| Trailer that needs stabilization at parking and loading time | Trailer landing gear product page | Landing gear solves support-leg needs, not king pin needs |
Engineering and Serviceability Details
The king pin is the connection point, not the whole coupling system
A king pin works together with the fifth wheel on the tractor. The part itself must be strong, correctly sized, and properly mounted because it carries the coupling load and allows safe articulation between tractor and trailer.
Material and manufacturing matter under repeated coupling cycles
High-strength alloy steel and cold forging are used to improve durability under repeated coupling, braking, road vibration, and weather exposure. That matters because the connection point is one of the most safety-sensitive parts on the trailer.
Why the weight class matters so much
Using a 50 mm king pin on a heavy-duty trailer that really needs a 90 mm connection class can create unnecessary wear and service risk. Matching the king pin to the trailer weight class is a basic procurement control, not an optional upgrade decision.
Why the page keeps an AggregateOffer structure
This is a family page with multiple forms, mounting options, and two major size classes. A range price is more accurate than a single fixed number because the exact cost depends on the model, mounting style, and production detail selected by the buyer.
Price and Procurement Guidance
Buyers should send the trailer gross weight, coupling standard, mounting preference, and whether the request is for a standard-duty or heavy-duty trailer. Kales can then match the right king pin size and give a quote that fits the actual trailer program rather than a generic parts number.
Inspection Views
Built for your market
- Adjust trailer dimensions, payload target, and axle layout to fit your cargo profile.
- Select suspension, tire specification, landing gear, ramps, sidewalls, or tanker compartments as needed.
- Choose structural details such as steel thickness and reinforcement based on road conditions.
- Apply OEM branding, company colors, and market-specific safety markings before shipment.
Export shipping made practical
- Shipment can be arranged by bulk vessel, Ro-Ro, container, or sea-road intermodal solutions depending on trailer size and destination.
- Standard stock units can move quickly, while custom production is scheduled according to quantity and configuration complexity.
- We support major trade terms including FOB, CIF, and CFR, and prepare export documents for customs clearance.
- Before shipment, photos, videos, and pre-delivery inspection records can be shared for confirmation.
Quality checks and after-sales
- Each trailer goes through factory inspection for welding quality, structural alignment, and key running components before delivery.
- We support certification and export document preparation according to your destination market requirements.
- A 12-month warranty is available for the main beam and key components, with spare parts and remote technical support after delivery.
How the order moves
Share your target market, usage scenario, and preferred configuration.
Receive our model recommendation, specification review, and factory quotation.
Confirm production, inspection, shipment route, and export documents.
Stay supported after delivery with spare parts and remote assistance.
Export shipping options
At Kales Vehicle, we keep freight planning practical so your trailer or truck reaches the destination with the right balance of protection, speed, and cost.
Container Shipping, Ro-Ro (Roll-on/Roll-off), and Bulk Cargo each serve different export needs, and we choose the safest route, loading method, and packing approach for the order.
Ro-Ro Cargo
Ro-Ro shipping method for Kales commercial trailers, driving directly onto the vessel for maximum safety.
Bulk Cargo Ship
Bulk cargo transport of stacked Kales semi trailers with wax spraying protection against seawater corrosion.
Questions before ordering
What is the difference between 50 mm and 90 mm king pins?+
The 50 mm king pin is intended for standard semi-trailer service up to 40 tons gross weight, while the 90 mm king pin is intended for heavier-duty trailers above 40 tons and up to 100 tons.
Is this the same as a fifth wheel coupling?+
No. The king pin is the trailer-side connection point. The fifth wheel coupling is the tractor-side device that locks onto it.
Can Kales supply welded and assembled versions?+
Yes. This family includes welded and assembled mounting options depending on the trailer build requirement.
Why does the page use a price range?+
Because the family includes multiple sizes and mounting styles. Final cost depends on the exact model and production detail selected.
What should I send before asking for a quote?+
Send trailer gross weight, coupling standard, mounting style, and whether the application is standard-duty or heavy-duty.
Request King Pin Matching and Quote
If you need a 50 mm or 90 mm semi-trailer king pin, send your trailer gross weight, coupling standard, mounting preference, and destination market. Kales can then match the right king pin size and quote the correct replacement part for your fleet.