What Is a 5th Wheel and How Does It Work?

By: Jamie Page Deaton  | 
Pickup truck with a fifth wheel set-up towing a trailer.
Most fifth wheel safety systems are adjustable, so it should be easy to find one that will fit over your setup. See more truck pictures.
Steve Shepard/istockphoto

Many adventurous drivers who are just investing in their trucks often hear about a mysterious 5th wheel but aren't sure what it is or how it functions. So, what is a 5th wheel? It refers to a 5th wheel set-up, which is a type of hitching mechanism used primarily for connecting a large trailer or camper to the towing vehicle. This set-up is named for its design, which resembles the fifth wheel of a carriage, providing pivotal support to facilitate turns.

Unlike traditional towing methods that use a ball hitch located at the rear bumper, the 5th wheel set-up is mounted in the bed of the towing vehicle, offering a stronger, more stable connection that is ideal for towing large, heavy trailers. In this article, we'll explore the components, benefits, and considerations involved in a 5th wheel set-up, providing a comprehensive understanding of why it's a popular choice for recreational and professional towing needs.


Components of a 5th Wheel Set-Up

The 5th wheel set-up consists of several key components that work together to provide a secure and efficient towing experience. The primary components include:

5th wheel hitch: The centerpiece of the set-up, this large, horseshoe-shaped device is mounted to the bed of the towing vehicle. It features a jaw mechanism that locks around the kingpin of the trailer. Alternatively, you can use a gooseneck hitch.


Kingpin: A pin that protrudes from the bottom front of the trailer, fitting securely into the hitch's jaw, creating the primary connection point between the trailer and the towing vehicle.

Mounting rails: These metal rails are installed in the bed of the towing vehicle and serve as the base for the 5th wheel hitch. They must be securely attached to the vehicle's frame to handle the weight and stress of towing.

Slider hitch: For short-bed trucks, a slider hitch may be used to provide additional clearance between the trailer and the cab of the vehicle during turns, preventing the trailer from hitting the cab.


Benefits of a Fifth Wheel Trailer

A fifth wheel setup is a great way to go RVing, tow heavy trailers, or go camping. Fifth wheel trailers can haul heavier loads than traditional hitch setups, and because the trailer can pivot, turning is a lot easier too. Plus, you get some extra living space out of the upgrade, which can be a fun project in itself!

Instead of being hitched to the back of the tow vehicle, fifth wheel setups are attached with a coupling pin on the front of the trailer and fifth wheel at the rear of the towing vehicle. The fifth wheel is shaped like a horseshoe, and gets its name from the fact that it turns like a wheel (that's what makes fifth wheel setups more maneuverable than a simple towing trailer). But just like with other towing setups, fifth wheel RVs and trailers have unique safety concerns.


Safety Issues With Fifth Wheels

The most common safety issue with fifth wheel hitches is dropping the trailer. Often, after hooking the trailer to the truck, people will forget to latch the coupling pin. When the truck starts to move, the trailer comes free of the fifth wheel and falls into the bed of the truck, causing major damage to both it and the trailer. The trailer could also fall into the road.

Fifth wheel safety systems combat this problem by providing foolproof protection. Most are simple devices that prevent the coupling pin (or "king pin") from slipping out. These towing accessories are key pieces of equipment that can greatly enhance towing safety. Keep reading to find out how to install and use fifth wheel safety systems.


Installing and Using Fifth Wheel Safety Systems

Pickup truck with fifth wheel hitch and trailer parked in a residential driveway.
Fifth wheel systems can haul heavier loads than traditional hitch setups.
Sebastian Iovannitti/istockphoto

Installing a fifth wheel safety system is a fairly straightforward process. Most fit over the existing fifth wheel setup. Though specifics vary, most fifth wheel safety systems consist of a mounting bracket that fits over the fifth wheel on the tow vehicle, crossbars that go over the fifth wheel but allow the trailer coupling to mount the wheel, and some sort of mechanism to prevent the king pin from coming loose.

In some cases, that mechanism is a door that opens only one way (to allow installation) and stays shut, holding the pin in place. In others, the mechanism catches the king pin before it comes loose.


To install a fifth wheel safety system, you first need to find one that fits over your setup. Luckily, most safety systems are adjustable. Since the safety systems fit over the existing fifth wheel hitch setup, you don't have to drill into the truck bed. You simply have to mount the safety system and bolt it into place. Installation shouldn't take very long or require tools beyond a basic set of wrenches.

Durability of the Fifth Wheel Design

The nice thing about most fifth wheel safety systems, in contrast to other towing accessories, is that once they're installed, they don't require any extra steps to use. Once the safety system is mounted, you can hitch up your trailer and use it normally. That's the beauty of these systems: they're so foolproof that they don't even change how you attach your trailer to your truck.

Still, as with all towing safety systems, you can't rely on fifth wheel safety systems to do all the work for you. Once the safety system is installed, you'll still need to inspect all of your trailer's components —including the safety system — to ensure that your fifth wheel RV is ready for action.


Also, just because the safety system will catch the king pin doesn't mean that you can forget about latching it securely into place. You still need to latch the king pin normally. You should also inspect your fifth wheel safety system every time you tow something, and observe all towing safety rules every time you're hauling something.

Enjoy the Power of Fifth Wheels

A 5th wheel set-up is an efficient and secure method of towing large trailers, offering improved stability, increased towing capacity, and enhanced safety over traditional towing methods. While it requires a compatible vehicle and an initial investment, the benefits of a 5th wheel set-up make it a popular choice for recreational and professional towing alike.

Whether you're daydreaming about a fifth wheel pickup truck, RV, or trailer, it's essential to consider the specific towing needs and the capabilities of the towing vehicle. By understanding the components, benefits, and considerations involved in a 5th wheel set-up, individuals can make informed decisions that ensure a safe and enjoyable towing experience.


This article was updated in conjunction with AI technology, then fact-checked and edited by a HowStuffWorks editor.

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