About Truck Bed Lengths
When 5th Wheel Trailers first appeared on the market, most trucks had boxes that were at least 6 1/2 Feet, if not 8 feet. But as our desire for larger cabin space grew and double cab and crew cab configurations became the norm, the bed sizes shrunk.
Today, most half-ton pickup boxes are just 5 1/2 Feet long, even 6 1/2 feet is now the exception. Only when you upgrade to a 3/4 or full one-ton pickup, does the standard bed go back up to 6.5 or 8 ft. in length.
The Need for Sliding Fifth Wheel Hitches
In a fifth-wheel towing configuration, shorter bed lengths mean that the nose of your trailer will be closer to the back window of the cab. This is usually fine when you are traveling in a straight line down the road.
But it is when you need the turning capabilities to make a tight 90-degree turn that you could run into problems with a short box. When you need a tight turn and the truck and trailer are too close together, the noise of the trailer will take out your back window. This can occur when you need to make a turnaround in a tight space or while backing into a campsite.
This is not a positive towing experience. So the industry solution to help with this issue was developed: the sliding 5th wheel hitch.
Manual versions of these trailer hitches allow you to unlock the hitch head and legs from the mounting system and slide it back when you need to make a tight turn. These usually allow you the additional clearance of up to 11 inches.
There are also automatic sliding hitches that use a channel system that knows when you are starting to make a tight turn. They then automatically move the hitch head back along the channels and return the head forward only when you have straightened the towing combination out again.
Assessing the Need for a Fifth Wheel Slider
To save you some time, if you have a 5.5-foot truck bed, you definitely need a sliding hitch. If your truck has an 8-foot box, in most cases you don't need a slider. However, if your trailer nose is well forward of the trailer king pin, you may want to use the calculation below to double-check.
For a 6.5' truck bed, you should check using this formula to calculate the need for a slider and the length of travel required:
First, measure the distance from the center of the axle on the truck to the back window. The axle will be directly below the center of the wheel wells from front to back. Call that measurement "A".
Get the distance from the center of the king pin to the forwardmost point on the nose of the trailer. If the nose is behind the kingpin, make this a negative number. This is measurement "B"
Subtract B from A. (Note: if B is negative, that will make the result greater than A)
Measure the overall width of your trailer (measurement "C") and divide by 2. This will be the distance you will need to clear when the truck is at 90 degrees to the trailer. Add Four Inches for a safety clearance.
Deduct the value you got by subtracting B from A from half the overall trailer width (plus the safety clearance.) This will give you the amount of travel you need to have available in your slider.
To summarize this formula:
(C+4 inches) - (A-B) = Amount of Hitch Travel Required
If the result of this calculation is a negative number, you probably don't need a slider hitch.
Recommended Types of Slider Hitches
If you have a 5.5 ft. box, you have only two choices if you want to tow a fifth wheel. These are the only hitches on the market that offer 22 1/2 inches of travel.
This is the amount of hitch travel distance you will need on a super short box. They are:
Pullrite #3100 Superglide - 12,000 lb. towing capacity
Demco 13K Autoslide Hitches - 13,000 lb. towing capacity
For 6.5' or 8' truck beds, you will probably only need 11-13" of travel to prevent cab window damage during turns. RV part shop has a wide variety of slider hitches to fit all vehicles and budgets. We offer all major product lines of Fifth Wheel hitches, including heavy-duty hitches from:
Slider hitches are available in different mounting configurations, including industry-standard rails (ISR). This is a fifth wheel hitch bed mounting standard that allows any ISR-compatible hitch to be connected on ISR Rails.
Another fifth wheel hitch mounting system uses a gooseneck ball as a single mounting point. These hitches have ratcheting systems that pull the hitch down tight against the ball, so the hitch is unable to move. This is the perfect system for anyone who tows both a fifth wheel and a gooseneck trailer.
Several manufacturers make OEM "puck" mounted hitches. "Pucks" are also referred to as "fifth wheel prep kits" and they are mounts built into the bed by the truck's manufacturer.
There are a small number of hitches that have proprietary mounting systems as well
If you don't want to use a sliding hitch, there are king pin extenders and fifth wheel to gooseneck adapters that can be used to move the kingpin pivot point back from the center of the hitch.
Reese also makes the Sidewinder Pin Box. This pin box replacement effectively provides the 22" of travel needed for short bed pickups with an articulating pin box arm. These are available in multiple original pin box mounting configurations.
Need more Help?
Feel free to call, chat or message us for assistance in configuring a fifth-wheel towing solution for your truck and trailer combination.