The best extended pin boxes for fifth wheels improve stability, reduce chucking, and restore compatibility with older hitch setups. This guide highlights five options that suit different trailering needs—from heavy towing to bolt-on ease. Ideal buyers include RV enthusiasts upgrading an older trailer, owners seeking a stronger weight capacity, and those prioritizing a maintenance-friendly install.
| Product | Brand | Weight Capacity | Best For |
|---|---|---|---|
| Lippert L05 Extended 5th Wheel Pin Box | Lippert Components | 18,000 lbs | Owners replacing worn 1621HD boxes |
| Lippert L05 SHD Extended 5th Wheel Pin Box | Lippert Components | 21,000 lbs | Heavy-duty applications and restored setups |
| CURT L05 Air Ride 21K | Lippert Components | 21,000 lbs | Best for minimizing chucking with air ride |
| MORryde Rubber Pin Box | MORryde | 18,001 lbs | Smooth ride with reduced chucking |
| Shocker 5th Wheel To Gooseneck Pin Box Replacement | Shocker Hitch | Up to 24,000 lbs | Replace-to-gooseneck setups on Lippert L05/L05 variants |
Lippert L05 Extended 5th Wheel Pin Box
Best for: Replacing worn 1621HD boxes with a bolt-on installation. This model is designed to connect to any 5th wheel hitch and restores trailer function quickly. The box bolts onto existing hardware along two bolt-hole rows, simplifying installation.
Why selected: It offers a straightforward upgrade path for aging rigs and maintains compatibility with common hitch systems. The extended design helps improve towing stability on extended pin boxes.
Caution: Ensure your trailer frame matches the two-row bolt configuration before installation. Verify compatibility with your current gooseneck or hitch setup.
Lippert L05 SHD Extended 5th Wheel Pin Box
Best for: Heavy-duty applications where higher weight tolerance is needed. The SHD version shares the L05 design but with enhanced capacity, making it suitable for larger fifth-wheel trailers and demanding terrains.
Why selected: Higher capacity supports tougher loads and longer trips, contributing to longer component life when towing heavy setups.
Caution: Installation requires careful alignment with existing bolt holes; improper positioning can affect alignment and towing feel.
CURT L05 Air Ride 21K Fifth Wheel Pin Box
Best for: Reducing chucking and road shock with an integrated air suspension system. This model is designed to replace Lippert 1621 pin boxes on suitable frames with air ride benefits.
Why selected: The air ride feature can noticeably smooth towing vibrations, especially on longer trips or rough roads, improving comfort and stability.
Caution: Air systems may require occasional maintenance; confirm fitment with Lippert 1621-compatible frames and air line routing.
MORryde Rubber Pin Box Fifth Wheel
Best for: Those seeking a cushioned ride with reduced chucking and jerking on uneven roads. MORryde offers a rubber-pin-box design that offsets road imperfections effectively.
Why selected: The cushioning helps create a steadier towing feel and reduces fatigue over long hauls, making it a strong everyday-use option.
Caution: Ensure the rubber pin box is compatible with your existing fifth-wheel frame and king pin dimensions before swapping.
Shocker 5th Wheel To Gooseneck Pin Box Replacement
Best for: Replacing a factory pin box to enable a gooseneck setup, compatible with Lippert 1621, 0719 RhinoBox, FlexAir, Rota-Flex, and L05 boxes. Ideal for converting to gooseneck towing when needed.
Why selected: It supports a conversion path for users who want flexible hitch configurations without buying a new trailer or hitch system.
Caution: This is a replacement pin box option; ensure your truck bed and hitch setup can accommodate the gooseneck conversion safely.
Buying Guide
Key considerations when choosing an extended pin box for a fifth wheel include weight capacity, compatibility with existing frames, and installation effort. Compare bolt-on options to determine how they align with your trailer’s bolt-hole spacing and king pin alignment. For smoother towing, consider models with air-ride or cushioned features, such as MORryde or CURT Air Ride variants. If you plan frequent gooseneck conversions, a Replacement Pin Box or SnapLatch-compatible option may be most convenient.
Frequently Asked Questions
- What is the advantage of an extended pin box? It increases ground clearance and can improve towing stability by better aligning the trailer with the hitch geometry.
- Can I replace my Lippert 1621 with an L05? Yes, many L05 variants are designed to replace 1621 pin boxes and bolt on with existing hardware.
- Do air-ride pin boxes reduce chucking? Yes, air-ride systems like CURT L05 Air Ride mitigate road shock and chucking.
- Is a heavier weight capacity always better? Not always; ensure compatibility with your trailer and tow vehicle and consider balance with tongue weight and payload.
- Do these require professional installation? Some bolt-on installations are straightforward for DIY enthusiasts, but others may benefit from a professional install for precise alignment.
- Will replacing the pin box affect warranty? Replacements can influence warranties; check your trailer and hitch warranties before proceeding.