Answer: Weld-on king pins are best for heavy-duty, long-haul setups where a strong, permanent connection to a 5th wheel trailer is required. They suit fleet operators, truckers, and trailer enthusiasts who want reliable, high-strength components that endure demanding towing conditions. Below are five well-matched weld-on king pins, each chosen for a specific need—strength, compatibility, or ease of installation—so you can compare quickly and pick the right fit for your rig.
Buyer’s quick-reference summary: 1) Buyers Products KP20050 (strong, standard 2″ king pin, 0.50″ bolster plate) 2) Buyers Products KP20038 (2″ king pin, 0.38″ bolster plate) 3) Queencar WA15 5050 (2″ collar, 3/8″ bolster plate) 4) Mytee Products Kingpin Weld On 0.38″ (USA-made, 2-pack) 5) World American (2″ collar, 3/8″ bolster plate)
Product Comparison Table
| Product | Brand | Profile | Bolt Plate Thickness | Notes |
|---|---|---|---|---|
| KP20050 Forged Trailer King Pin | Buyers Products | 2″ SAE king pin | 0.50″ | High strength; weldable; general use |
| KP20038 Forged Trailer King Pin | Buyers Products | 2″ SAE king pin | 0.38″ | Balanced strength and weight |
| WA15 5050 Forged King Pin | Queencar | 2″ collar | 3/8″ | OE-style design; high load capacity |
Buyers Products KP20050 Forged King Pin
- Best for: Fleets needing strong, durable 2″ king pins with higher bolster plate thickness for long-lasting performance.
- Key features: 2″ SAE king pin; hardness maintained at 302-363 BHN; weldable for secure attachment.
- Who should avoid: If you require the lighter 0.38″ bolster plate, this may be heavier than needed.
2″ Weld-On King Pin, 3/8″ Bolster Plate
- Best for: Replacements where a standard 2″ collar and 3/8″ bolster plate are compatible with existing gooseneck hardware.
- Notes: Brand listed as National Drivetrain; verify compatibility with your trailer’s fifth wheel setup.
Buyers KP20038 Forged King Pin
- Best for: Users needing a slightly lighter bolster plate while maintaining strong forging.
- Notes: Similar hardness profile to KP20050; ensure bolster plate thickness suits vehicle frame.
Mytee Kingpin Weld On 0.38″ (2 Pack)
- Best for: Buyers wanting a USA-made option with a 2-pack for convenience and replacement planning.
- Notes: Made from 8630 alloy steel; check exact compatibility with your trailer model.
Mytee Kingpin Weld On 0.38″ USA
- Best for: Applications requiring high ultimate and yield strength figures, with USA production.
- Notes: Available in 8630 alloy steel; ensure your welding setup matches the material requirements.
World American Weld-On King Pin 2″ Collar
- Best for: Standard 2″ collar applications where a proven, widely available option is preferred.
- Notes: Brand emphasis; verify bolster plate thickness compatibility with existing components.
Buyers BKPT809B Forged King Pin
- Best for: Fleet operators seeking a forged, heat-treated option with multiple holes for mounting options.
- Notes: 0.50″ bolster plate thickness provides additional strength; confirm hole pattern compatibility.
Buying Guide: Weld On King Pins For 5th Wheel Trailers
Key purchase considerations help identify the right weld-on king pin for your trailer and application.
- Strength and material: Look for forged steel with heat-treating or high-hardness ratings to withstand heavy loads and repeated hooks.
- Bolt plate thickness: A thicker bolster plate generally offers higher strength, but ensure it matches your trailer’s gooseneck or mounting frame.
- Compatibility: Confirm collar size (2 inches is common) and whether the pin design matches your fifth wheel hitch or tow package.
- Welding requirements: Verify that the king pin is designed for weld-on installation and that your welding process (material compatibility, preheat, post-weld treatment) aligns with manufacturer guidance.
- Manufacture and sourcing: Reputable brands with consistent quality control reduce the risk of premature wear or failure under load.
- Maintenance considerations: Some pins emphasize inspection and testing; plan periodic checks as part of trailer maintenance.
Practical buyer questions
- What makes a 0.50″ bolster plate different from a 0.38″ plate? Higher plate thickness generally supports greater load and stiffness, but may add weight and require compatible mounting hardware.
- Is a 2″ collar standard? Yes, most gooseneck and fifth-wheel pins use a 2″ collar; verify compatibility with your hitch.
- Do I need a USA-made king pin? USA-made options often prioritize material quality and consistent manufacturing, which can matter for heavy use fleets.
- Can I mix brands? Mixing brands is not recommended; use pins and plates designed to work together within your trailer’s weight class and hitch system.
- How do I determine the right bolster plate thickness? Base your choice on trailer weight rating, expected loads, and manufacturer recommendations for your specific wheel base and frame.
FAQ
- Q: Are weld-on king pins interchangeable between brands? A: Not always; check collar size, bolt pattern, and plate thickness for compatibility.
- Q: How often should king pins be inspected? A: Regular inspection during maintenance cycles is recommended; look for wear, cracking, or deformation.
- Q: Can I weld a king pin onto any trailer frame? A: Welding requirements depend on frame material and design; follow manufacturer instructions and local regulations.
- Q: Do bolt holes matter for installation? A: Yes; correct hole alignment ensures secure mounting and proper load transfer.
- Q: Which option is best for high-mileage fleets? A: Options with higher bolster plate thickness and forged construction tend to be more durable under continuous use.