When it comes to heavy-duty towing, few setups are as popular and capable as 5th wheel and gooseneck hitches. Both are designed for hauling substantial loads—RVs, horse trailers, equipment trailers, and more—but they connect to the truck in different ways.

So what happens when you have a truck equipped with a gooseneck hitch, but your trailer is designed for a 5th wheel connection?

That’s where a 5th wheel to gooseneck adapter comes in.

Understanding the Difference: 5th Wheel vs. Gooseneck

Before diving into adapters, it’s helpful to understand the core difference between the two hitch types.

5th Wheel Hitch

• Uses a large, horseshoe-shaped hitch plate mounted in the truck bed.
• The trailer connects via a kingpin, similar to a semi-truck setup.
• Commonly used for:
• RVs
• Toy haulers
• Large travel trailers

5th wheel hitches are known for:

• Excellent stability
• Smooth ride characteristics
• Strong weight distribution

However, they are:

• Heavy
• Bulky
• Often semi-permanent in the truck bed

Gooseneck Hitch

• Uses a ball hitch mounted in the bed of the truck.
• The trailer has a coupler that drops over the ball.
• Commonly used for:
• Livestock trailers
• Flatbeds
• Equipment trailers
• Agricultural applications

Gooseneck systems are popular because:

• The ball is compact and often removable or fold-down.
• The truck bed remains mostly clear when not towing.
• They’re extremely durable for commercial use.

What Is a 5th Wheel to Gooseneck Adapter?

A 5th wheel to gooseneck adapter is a device that allows a trailer designed with a 5th wheel kingpin to connect to a gooseneck ball hitch instead.

In simple terms, it converts the kingpin into a gooseneck-style coupler.

There are two main styles:

1. Kingpin Extension Adapters
   These attach to the existing kingpin and extend downward to connect to a gooseneck ball.
2. Replacement Pin Boxes (Gooseneck Pin Boxes)
   These replace the entire 5th wheel pin box with a gooseneck-compatible unit, often engineered for better structural support.

The Primary Purpose: Hitch Compatibility

The primary use of a 5th wheel to gooseneck adapter is straightforward:

To allow a 5th wheel trailer to be towed by a truck equipped with a gooseneck hitch.

This is especially useful when:

• The truck already has a factory-installed gooseneck ball.
• The owner does not want to install a full 5th wheel hitch.
• The truck is used for multiple trailer types.

Rather than investing in additional hitch hardware, an adapter provides flexibility and convenience.

Why People Choose an Adapter

1. Cost Savings

Installing a 5th wheel hitch can be expensive. Between the hitch itself and potential installation labor, costs can add up quickly.

A 5th wheel to gooseneck adapter is often:

• Less expensive
• Easier to install
• A practical short-term solution

For occasional towing, this can make financial sense.

2. More Usable Truck Bed Space

One of the biggest advantages of a gooseneck setup is space.

• A 5th wheel hitch can weigh over 100–200 pounds.
• Removing it can require multiple people.
• It takes up a large portion of the truck bed.

In contrast:

• A gooseneck ball is compact.
• Many designs are removable or fold flat.
• The truck bed remains largely clear for cargo.

For contractors, ranchers, or equipment haulers who need versatility, this is a major benefit.

3. Multi-Trailer Flexibility

Many truck owners tow multiple trailer types.

For example:

• A livestock trailer (gooseneck)
• A flatbed equipment trailer (gooseneck)
• An RV (5th wheel)

With an adapter, one truck setup can handle them all without swapping hitches.

How a 5th Wheel to Gooseneck Adapter Works

The adapter connects to the trailer’s existing kingpin assembly and extends downward to meet the gooseneck ball in the truck bed.

Instead of the kingpin locking into a 5th wheel plate, the adapter:

• Positions a coupler over the gooseneck ball.
• Transfers the trailer’s weight through the ball mount.

This changes the geometry of how forces are distributed between the truck and trailer—something that becomes important when evaluating safety and long-term durability.

Important Structural Considerations

While adapters offer convenience, they also introduce mechanical differences that must be considered carefully.

1. Stress Distribution

Traditional 5th wheel hitches:

• Spread forces across a wide hitch plate.
• Distribute weight more evenly.

Kingpin extension adapters:

• Add leverage below the original pin box.
• Can increase stress on the trailer frame.

This added leverage may:

• Affect ride quality.
• Increase frame strain.
• Potentially void manufacturer warranties.

For this reason, some trailer manufacturers discourage simple extension adapters.

2. Manufacturer Warranty

Many RV and trailer manufacturers specify:

• Approved hitch types.
• Compatible connection systems.

Using a non-approved adapter can:

• Void structural warranties.
• Shift liability in the event of frame damage.

Before installing an adapter, it’s critical to:

• Review your trailer’s warranty documentation.
• Contact the manufacturer for confirmation.

3. Weight Ratings Matter

Always verify:

• The adapter’s weight rating (GTW and tongue weight).
• The truck’s gooseneck rating.
• The trailer’s GVWR.

All components in the towing system must be rated to handle the load safely.

Never assume compatibility based solely on fit.

Replacement Pin Boxes: A Better Long-Term Option?

Instead of a simple extension adapter, many experts recommend gooseneck pin box replacements.

These units:

• Replace the entire 5th wheel pin box.
• Are engineered specifically for gooseneck towing.
• Often include built-in shock absorption or cushioning.

Advantages include:

• Improved structural integrity.
• Reduced frame stress.
• Better ride quality.
• Greater manufacturer approval likelihood.

For full-time RVers or frequent haulers, this is often the superior solution.

Common Applications

5th wheel to gooseneck adapters are commonly used for:

• RV 5th wheel trailers
• Horse trailers
• Equipment haulers
• Toy haulers
• Agricultural trailers

They are especially popular among:

• Ranchers
• Contractors
• Fleet operators
• Multi-trailer owners

When Is an Adapter a Good Idea?

A 5th wheel to gooseneck adapter may make sense if:

• You tow occasionally.
• Your trailer manufacturer approves it.
• Your weight ratings are well within limits.
• You prioritize bed space flexibility.
• You want to avoid installing a heavy 5th wheel hitch.

When Should You Reconsider?

You may want to look at alternatives if:

• You tow frequently or full-time.
• Your trailer is near its maximum weight capacity.
• Your manufacturer discourages extension adapters.
• Ride quality and long-term structural integrity are top priorities.

In these cases, either installing a proper 5th wheel hitch or upgrading to a replacement gooseneck pin box may be the better route.

Final Thoughts

A 5th wheel to gooseneck adapter is a practical and often cost-effective solution for matching a 5th wheel trailer with a gooseneck-equipped truck. Its primary purpose—hitch compatibility—offers flexibility, bed space savings, and convenience for many truck owners.

However, convenience should never outweigh safety.

Understanding how these adapters change load distribution, verifying weight ratings, and reviewing manufacturer guidelines are all essential steps before making the switch.

When properly selected and installed, the right adapter can provide a versatile towing setup that meets your needs—without sacrificing performance or reliability.