Answering the need for durable, weldable king pin plates, this guide highlights reliable options for semi trailers. These picks are best for fleet managers, owner-operators, and maintenance teams seeking strong, long-lasting king pins that fit 2″ collars and bolster plates. The top picks emphasize hardness, compatibility, and load support to help you choose the right plate for your 5th wheel.
| Product | Model / Features | Best For | Why It Stands Out |
|---|---|---|---|
| Buyers KP20050 | 2″ SAE king pin; 0.50″ bolster plate; Weldable | Maintenance teams needing balanced strength and adaptability | Solid hardness range; broad compatibility with standard fifth wheels |
| ELSOON WA15 5050 | 2″ collar; 3/8″ bolster plate; Forged steel | Heavy-duty towing on diverse trailers | High-strength forged construction for longevity |
| Buyers KP20038 | 2″ SAE king pin; 0.38″ bolster plate | Cost-conscious upgrades with solid support | Reliable performance at a thinner bolster plate |
| Buyers KP20031 | 2″ SAE king pin; 0.31″ bolster plate | Budget-friendly installations with consistent support | Lightest bolster plate among options; simpler install |
| Brilluxa WA15 5050 | 2″ collar; 3/8″ bolster plate; WA15 5050 compatible | Specialty replacements with OE references | Replacement-grade option with clear compatibility notes |
Buyers Products KP20050 Forged King Pin
The KP20050 uses a 2″ SAE king pin and offers a 0.50″ bolster plate thickness. It is weldable for reinforced fifth wheels. This model aligns with Buyers Products’ broader line, which includes snow and ice equipment, hardware, and trailer components. Best for fleets needing a robust, weldable plate that supports standard 5th wheel connections.
Who it’s best for: maintenance teams and operators who require a strong, weldable king pin with moderate bolster plate thickness. Why selected: combines reliable hardness in the 302-363 BHN range with practical compatibility across common trailer hardware.
Limitation: data does not specify exact load ratings beyond hardness and general compatibility; verify compatibility with your 5th wheel before ordering.
ELSOON WA15 5050 Forged King Pin
ELSOON WA15 5050 is a forged steel king pin designed for 5th-wheel trailers, featuring a 2″ axle collar and a 3/8″ bolster plate. Built for heavy-duty towing, it supports long-term use in demanding conditions and fits a wide range of fifth-wheel and gooseneck trailers.
Who it’s best for: operators needing high-strength forging for long-term reliability on heavy trailers. Why selected: forged steel construction and specific collar/ bolster plate dimensions support tough towing scenarios.
Caution: compatibility is stated for WA15 5050 variants; confirm your exact model matches before purchase.
Buyers KP20038 Forged King Pin
The KP20038 uses a 2″ SAE king pin with a 0.38″ bolster plate and weldable construction. It mirrors Buyers Products’ emphasis on durability and cross-compatibility with trailer hardware. This option is useful for those who want reliable performance with a thinner bolster plate.
Who it’s best for: fleets needing a dependable reinforcement with moderate bolster thickness. Why selected: balance of strength and cost, plus continued alignment with Buyers’ product ecosystem.
Limitation: bolster plate is thinner (0.38″), which may influence load-bearing expectations in very heavy-duty use.
Buyers KP20031 Forged King Pin
The KP20031 is another 2″ SAE king pin option with a 0.31″ bolster plate. It emphasizes weldable construction and aligns with Buyers Products’ engineering approach across the 2″ king pin family.
Who it’s best for: buyers prioritizing the lightest bolster plate among the Buyers lineup for easier installation or lighter-duty applications. Why selected: compact bolster plate thickness can simplify retrofits where weight or clearance matters.
Caution: thinner bolster plates may limit load-handling capabilities compared with thicker options.
Brilluxa WA15 5050 Kingpin
Brilluxa Kingpin is a WA15 5050 compatible replacement king pin with a 2″ collar and a 3/8″ bolster plate. It targets replacement scenarios and OE-referenced compatibility. This makes it a practical option for those seeking a straightforward swap with clear model references.
Who it’s best for: operators replacing worn king pins with known compatibility references. Why selected: provides a dependable option for models that match WA15 5050 specifications.
Limitation: ensure exact OE compatibility with your trailer model to avoid mismatches in fitment.
Buying Guide
What to consider when choosing a king pin plate for a semi trailer:
- King pin size and collar compatibility: Most common is a 2″ collar; confirm your fifth-wheel hitch specifications before purchase.
- Bolt-on vs weldable: Weldable plates offer permanent reinforcement, while bolt-on varieties can be swapped more easily for maintenance.
- Bolster plate thickness: Thicker plates (0.50″ or more) typically provide greater load distribution and durability; thinner plates may suit lighter-duty use.
- Material and hardness: Forged steel and high-hardness ranges (such as 302-363 BHN) indicate strong, wear-resistant performance under heavy loads.
- Compatibility notes: Some products specify compatibility with WA15 5050 or other OE references; verify model alignments with your trailer.
- Installation considerations: Check whether your trailer frame allows for weldable reinforcements and ensure proper welding procedures are followed.
FAQ
- What is a king pin plate used for on a semi trailer?
- What does bolster plate thickness affect?
- Is a weldable king pin plate better than bolt-on?
- How do I know which WA15 5050-compatible king pin to buy?
- Can I replace a king pin plate by myself?
- What’s the key difference between 0.31″, 0.38″, and 0.50″ bolster plates?
A king pin plate reinforces the king pin area where the trailer connects to a fifth wheel, offering strength and wear resistance for secure towing.
Bolster plate thickness affects load distribution and durability. Thicker plates typically support heavier loads and longer service life.
Weldable plates provide permanent reinforcement, while bolt-on plates offer easier removal or replacement. The choice depends on maintenance needs and trailer design.
Check your trailer’s OE references and model compatibility. Look for 2″ collar and 3/8″ bolster plate specifications identical to your current setup.
Yes, provided you have the correct tools and follow proper welding or mounting procedures as applicable to your trailer and plate.
These values indicate thickness; thicker plates generally offer greater strength and load distribution, while thinner plates may suffice for lighter-duty usage.