How Fifth Wheel Towing Works

By: Josh Briggs

Tractor trailers tow with a fifth wheel.
Tractor trailers tow with a fifth wheel.

Driving a tractor trailer can be quite an experience. It's not like driving any other type of vehicle. The tractor or towing vehicle is always shorter than the trailers, which can reach 53 feet in length. With all the room to haul, you might think the trailer can out-muscle the truck. And you'd be right -- they can. But tractor trailers aren't the only types of vehicles with long trailers. What makes them unique is how they tow trailers.

What separates a tractor trailer from your common light-duty pickup truck is the presence of a fifth wheel. A fifth wheel isn't stashed somewhere on the undercarriage of the truck -- it's the hitch mechanism that connects the tractor to the trailer. When you tow a boat or a trailer with a pickup truck, for the most part you're using a trailer with a hitch and a hitch coupler. A fifth wheel takes the place of the hitch. The benefit of a fifth wheel is the turning radius, which can really be seen when the truck is backing up. A skilled driver can maneuver a trailer into tight spaces by turning the tractor at very sharp angles. It's not uncommon for a tractor trailer to form an L or right angle while backing up to a loading dock -- or even taking left and right turns on city streets.



­Light trucks can also be equipped with fifth wheels. Along with their turning advantages, fifth wheels are capable of handling much heavier trailer loads than small, hitch-based trailers. When a pickup truck is outfitted with a fifth wheel, it can become a smaller version of a tractor trailer. Fifth wheels are commonly mounted in the center of the truck bed, over the rear axel, which is the area that supports the most weight.

In this article, we'll provide some tips on driving a vehicle with a fifth wheel. On the next page we'll learn how to properly back up a trailer attached to a fifth wheel, give you some pointers on how to attach and detach trailers and inform you about driving through city traffic.


Fifth Wheel Towing Essentials

A pickup truck hauling a camper also uses a fifth wheel.
A pickup truck hauling a camper also uses a fifth wheel.
Paul Vasarhelyi/istockphoto

Fifth wheels are unlike conventional tow hitches in that they require more maintenance to operate. They are mechanisms, not machines, so you don't really need to worry about them breaking down -- but you do need do lubricate them often to prevent them from malfunctioning. Always keep a generous amount of lube on the lube plate or top of the fifth wheel. Axel or chassis grease will do the trick. Also, make sure the lube plate is free of any obstructions before coupling the trailer.

A fifth wheel works by locking a king pin into the lock jaw. It does kind of sound like a mob boss stepped on a rusty nail and got infected with tetanus. But seriously, these two mechanisms are the backbone of fifth wheel towing. The king pin is similar to a hitch coupler and is attached to the trailer, while the lock jaw acts as the hitch receiver. One the lube plate is all greased up and you've inspected the fifth wheel thoroughly, you're ready to connect the trailer or hook up.


Hooking up a trailer equipped with a king pin is different than connecting a conventional trailer. You don't drop the trailer onto the receiver. Instead, you push the fifth wheel up onto the trailer. Fifth wheel trailers are equipped with what's referred to as landing gear or jack legs. These keep the trailer suspended when it's not hooked up to a towing vehicle. Now, back your towing vehicle right up to the edge of the trailer and make sure the king pin is lined up with the throat, or opening of the fifth wheel. Next, hop out and adjust the height of the trailer so it's just about to touch the lube plate. Once you've determined everything is good to go, back the truck up. You'll feel resistance because the trailer will have to slide up the lube plate. Once the king pin slides into the lock jaw, you'll feel it and probably hear a loud clang. Before you raise the landing gear, pull forward just enough to make sure the trailer is secure. Be careful not to drag your gear. Raise the gear and you're ready to go.

When you're ready to uncouple, there's a lever on the side of the fifth wheel that opens the lock jaw and releases the king pin. In reverse order, drop your landing gear to the point where it's almost raising the trailer. Now pull the release lever to unhook the king pin. If you can't release the lever, chances are you have too much tension on the king pin. Make the necessary adjustments by moving the towing vehicle slightly (forward or reverse) or move the trailer up or down with the landing gear. Once the king pin is released and gear is down, pull the vehicle clear. It's that simple.

Now that you're ready to drive, let's mosey on over to the next section to learn some driving tips. After all, driving is the fun part, right? Let's find out on the next page.


Fifth Wheel Towing Techniques

Maneuvering a fifth wheel trailer is tricky -- especially in reverse.
Maneuvering a fifth wheel trailer is tricky -- especially in reverse.
Juan Monino/istockphoto

Towing a trailer can be difficult, even downright intimidating, especially for beginners. These tips should start to put you at ease. It's important not to fear towing a trailer when driving a vehicle with a fifth wheel. Even if you have no towing experience at all, remember that you are in control.

When you're driving a vehicle with a fifth wheel, chances are you're driving a rather long truck-and-trailer combination. That means turning can be a bear. You can't turn left at a four-way intersection in a tractor trailer like you can in a Honda Civic. Fortunately, a fifth wheel gives you a tremendous amount of turning angle. A good rule of thumb when turning a fifth-wheeled vehicle is to wait and drive the tractor or towing vehicle in deep before you make your turn. "Deep" means that you actually want to drive past the lane you are attempting to turn into. Instructors will often tell you to wait until you can't see your lane anymore if you're looking out the side window. When you make that late turn, you're allowing the rear axel to travel farther. Because trailers are so long, they need the extra distance so you won't cut off the front of a vehicle sitting in the opposite lane. The beauty of the fifth wheel is you can make that turn because there is no hindrance between the tractor and trailer -- at least not until you're near a 90 degree angle. Now let's kick it in reverse.


Mirrors are essential to towing, especially when you have a long trailer. If you're uncomfortable with using your mirrors, you better find a way to fix that. When it comes time to drive a trailer in reverse, you will absolutely rely on your mirrors. Don't waste time hanging out an open door and trying to look around your trailer -- it's unsafe and downright unpractical.

Whether you're backing into a loading dock or a parking spot, always position your truck and trailer perpendicular to the space. A good rule of thumb is to pull up a good 20 feet, if possible, so you have your trailer perfectly straight. Now here's what can make a fifth wheel so tricky -- but beneficial at the same time. The greater the distance from the fifth wheel to the trailer, the slower the rear will turn. This means the trailer will respond more slowly to the steering input -- but once it starts turning, it will turn very quickly.

If you have a shorter wheelbase on the tractor, the steering will be sharper. With a fifth wheel, you can really crank the tractor from side to side in order to maneuver the trailer. But we don't want to do that. We want to enter in the slightest steering actions possible. The more you turn the steering wheel, the easier it is to lose the back end of the trailer. Keep in mind that a reversing trailer moves in the opposite direction as the tractor or towing vehicle. If you want to turn the trailer left, you'll need to turn the steering wheel to the right. You'll want to pick a target on the driver's side that you want the trailer's wheel to touch, and always keep both wheels visible in your mirrors. If you can't see one side, you're turning too much. A fifth wheel gives you the flexibility to recover, but take it slow and don't get off the target with that tire.

Towing a trailer takes patience, confidence and plenty of practice. To read more towing tips on other aspects -- including shifting and braking -- visit the links on the next page.


Lots More Information

Related HowStuffWorks Articles

More Great Links


  • Job, Ann. "Towing Tutorial." MSN Autos. (Sept. 16, 2008)
  • RV Basics. "RV Fifth Wheel & Travel Trailer Towing Safety Tips." (Sept. 16, 2008)
  • Will, Oscar H. III. "A No-More-Tears Approach to Backing Up." Nov./Dec. 2006. (Oct. 12, 2008)