Fifth Wheel Towing

Fifth wheel towing starts with a quote from Wikipedia “Some recreational vehicles use a fifth wheel configuration, requiring the coupling to be installed in the bed of a pickup truck as a towing vehicle. The coupling consists of a kingpin, a 2-or-3 1⁄2-inch (50.8 or 88.9 mm) diameter steel pin on the front of the fifth wheel trailer, and a horseshoe-shaped coupling device called a fifth wheel on the rear of the towing vehicle. The surface of the semi-trailer (with the kingpin at the center) rotates against the surface of the fixed fifth wheel, which does not rotate. To reduce friction, grease is applied to the surface of the fifth wheel. The advantage of this coupling is improved towing stability.”

This improved towing stability is one of the main reasons fifth wheel trailers are so popular. Ease of maneuverability is another reason to choose a fifth wheel trailer over a travel trailer.

Fifth Wheel Hitches and Accessories

Fifth wheel towing setups used in RV’s  have been around for a long time. Modern fifth-wheels since the 1990’s can tilt to the sides and are easier to hook up because the coupler in the bed is “funneled” to capture the king pin on the trailer, which helps guide it into place.

Because fifth-wheel hitches are anywhere from 14 to 18 inches above the bed, they can be susceptible to chucking, where the coupler jaws grab the king pin. This is mainly a problem with less expensive setups. If you spend more on a better fifth-wheel hitch that adjusts to keep a tight grip on the king pin, and chucking is all but eliminated.

The fifth wheel towing hitch must also be able to handle the loaded weight of your trailer. In this case, buy a more capable hitch in case you upgrade in the future.

Standard Fifth Wheel Hitch

An important issue when you select a fifth wheel hitch is cab-to-axle ratio, or the distance from the back of the cab to the center point of the coupler, usually located above or slightly forward of the rear axle. Requirements for a full-size bed are a no less than 48 inches behind the cab. For a short-bed pickup to pull a fifth-wheel, the measurement can be as little as 38 inches if you also use a pin-box extension (12-18 inches) and slide rails for the coupler.

That  pin-box extension is attached to the trailer. Its function is to extend the pivot point, or king pin, farther forward. The load of the trailer still rests above the axle but the trailer’s front cap is farther to the rear to prevent  interference with the truck’s cab when turning. In addition to the pin box extension, a sliding style hitch is required which moves front to back to help with low speed maneuvering like backing into a space in a campground. You unlock the coupler from the slide rails, set the trailer brakes and pull forward. Once you lock the coupler in place, you will have clearance for backing and tight maneuvering. Before you leave, you will have to unlock the coupler and slide it forward and then lock it in place for regular driving. This will save you from having to get body work done on your trailer and truck. Isn’t fifth wheel towing fun?

Another fifth wheel towing accessory I see a lot is an air pin box. The air bag(s) help with the jolts the trailer takes from rough roads. There are also air hitches available.

You will probably have to remove the factory tail gate for fifth wheel towing, or buy a special tailgate with clearance for the trailer’s king pin.

Hooking up a Fifth Wheel Trailer

Back up far enough to ensure the king pin is in all the way and touching the front part of the coupler. Now pull the hand lever to lock the kingpin. Next, lift the trailer jacks as high as they will go. This is a good place to mention that you MUST ensure a solid mechanical lock between kingpin a d hitch receiver. Otherwise, when you drive forward, the kingpin will slide out and the trailer will drop on the bed of your pickup. You will probably see this “dent of shame” on other pickups in the campground that haven’t been repaired yet.  There is an accessory called a pin catcher that bolts on to the rear of the hitch that will catch and hold the pin so that the trailer doesn’t drop. Perhaps a wise investment. You might need an extension harness that carries the voltage for the marker and signal lights. Some fifth wheels require a harness with fuses and relays all their own, but usually the extension is a length of cable and two seven-blade connectors. Next, check your lights, turn signals and brakes. This brake check is where you will make sure the kingpin is secure in the hitch.

Fifth Wheel Towing Tips

I could have researched and written a small section of fifth wheel towing tips, but our friend Ray Burris at wrote a really great blog post on this subject.

Check it out here:

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