How to Measure Truck Bed for 5th Wheel & Gooseneck Clearance
How to Measure Truck Bed for 5th Wheel & Gooseneck Clearance
A CURT fifth wheel hitch is the ultimate combination of towing power and smooth driving, but a CURT fifth wheel mounted on a fifth wheel roller turns this gentle giant into the ultimate in mobility too. If you have a short-bed truck, it can be difficult and even dangerous to tow a large RV trailer, especially one with an extended front overhang. Around those tight corners, the front of the RV can come too close for comfort to the back of your truck cab. When you are towing a fifth wheel with a short-bed truck, give yourself a little breathing room with a CURT fifth wheel slider.
CURT fifth wheel sliders mount easily and securely into a set of industry-standard fifth wheel base rails already installed in the bed of your pickup truck. They feature solid construction and offer a sturdy mounting place for your fifth wheel hitch. CURT fifth wheel sliders are also true rolling units, meaning they roll on actual wheels rather than sliding on hollow rods, as seen in competitive models.
With a thick operating handle, the roller smoothly rolls the fifth wheel head forward and back, locking securely into each position as desired. CURT sliders provide up to 12” of displacement, unlike the more common 10”, to give you a wide range of motion and plenty of space to get your RV or other fifth wheel trailer around any turn.
CURT fifth wheel sliders come with a durable carbide powder coat to ensure the best possible protection against scratching, chipping, rusting and UV damage. CURT offers sliders in 16,000, 20,000 and 24,000-lb. capacities, making them compatible with most CURT fifth wheel hitches (limited by lowest-rated towing component).
CURT fifth wheel sliders are built and tested to be straight-forward in design, effective in function and safe to use. Like all CURT products, our fifth wheel towing equipment is put through strenuous SAE J2638 testing to ensure safety wherever the road takes you.
Both towing and hauling require you to know your truck bed length. Bed length is especially important when installing a 5th wheel or gooseneck hitch.
In this guide, we will compare truck bed sizes by make and model -- such as the Ford F150 truck bed size vs. Chevy truck bed sizes -- and then walk through a step-by-step process of measuring the truck bed for a 5th wheel or gooseneck hitch.
Truck Bed Size Chart
Make / Model
Chevrolet Silverado 1500
Chevrolet Silverado 2500 HD / 3500 HD
Ford F-250 / F-350 / F-450 Super Duty
GMC Sierra 1500
GMC Sierra 2500 HD / 3500 HD
Nissan Titan XD
Ram 2500 / 3500
*Data gathered from manufacturer websites for 2020 model years
for a 5th Wheel Slider: 3 Easy Steps
To determine if a sliding 5th wheel hitch is needed for your truck, there is a simple equation you can use:
the distance from the cab to the center of the 5th wheel hitch head or gooseneck ball hole (Y) minus half the width of the trailer (X).
Y - X = Z, the amount of trailer clearance.
This is true for short-beds and long-beds, regardless of truck bed length.
To measure for a 5th wheel slider, begin by measuring the width of the trailer at the front. At the forward-most point of the trailer, measure the distance across. Then, divide this distance in half.
Common trailer widths are 84”, 96” and 102”.
Alternatively, you can measure from the center of the kingpin to one side of the trailer. This will be half of the trailer width.
If your trailer has a taper at the nose, the general rule is as follows: 8-foot wide trailers taper to 6 feet at the coupler and 7-foot wide trailers taper to 5 feet at the coupler.
Step 2: Measure the truck bed (Y)
Next, measure from the back of the truck cab to the center of the 5th wheel hitch head or gooseneck hole. This is distance Y.
If your truck doesn’t have a 5th wheel hitch installed, you will need to determine where the coupling point will be.
If your trailer has an overhang that extends beyond the kingpin, this distance will need to be subtracted from measurement Y. In practical terms, we’re looking for the true distance between the truck cab and the trailer. This requires finding the forward-most point of the trailer, which may or may not be the kingpin.
Step 3: Calculate your truck-trailer clearance
Take the distance from the truck cab to the 5th wheel coupling point on the hitch and subtract half of the trailer width. Remember to also subtract any trailer overhang that extends beyond the kingpin.
Y - X = Z
(Cab to coupler) - 1/2 (trailer width) - (trailer overhang past the kingpin) = (minimum clearance)
If Z is a positive number, it means that the trailer will not obstruct the truck cab when making a turn. If Z is a negative number, it means the trailer will obstruct the truck cab when making a turn.
Example of measuring for a 5th wheel slider
5th wheel trailer
The distance from the truck cab to the center of the 5th wheel jaws is 41 inches. Next, the width of the trailer is 84 inches. Half of 84 is 42. 41 inches minus 42 inches is negative 1 inch.
41 - 42 = -1
Because the difference is a negative number, the trailer will interfere with the truck, creating an unsafe situation when attempting to make a turn. The solution is to install a sliding 5th wheel hitch instead of fixed legs.
For a trailer with overhang beyond the kingpin, let’s use the same example measurements. The distance from the cab to the 5th wheel jaws is 35 inches. Half of the trailer width is 42 inches. The nose of the trailer overhangs the kingpin by 4 inches. 35 inches minus 4 inches minus 42 inches is negative 11 inches.
(35 - 4) - 42 = -11
Because there is an 11-inch deficit, the trailer will interfere with the truck cab. A 5th wheel slider should be used.
Selecting a sliding 5th wheel hitch
If your truck bed does not provide enough clearance for the trailer (negative clearance), you will need a 5th wheel slider to properly install a 5th wheel hitch. If the clearance between your truck cab and trailer is positive but tight, a 5th wheel slider is also recommended.
A sliding 5th wheel hitch will provide extra clearance between the truck cab and trailer by sliding the coupling point rearward by several inches. Remember to select a slider that meets or exceeds the weight capacity of your hitch.
1. How do I know if I need a sliding 5th wheel hitch?
If the distance from your truck bed to your 5th wheel jaws is less than half the width of your trailer, you will need a sliding 5th wheel hitch. Without a slider, the nose of the trailer will obstruct the truck cab when making a turn.
2. Can you put a 5th wheel in a short bed truck?
Yes, you can put a 5th wheel hitch in a short bed truck, as long as the trailer nose won’t obstruct the truck cab. If half the trailer width is greater than the distance from the truck cab to the coupling point, a sliding 5th wheel hitch can be used, giving the short bed truck the additional clearance needed to make turns. CURT offers 5th wheel towing options for most pickup truck bed sizes.
3. Do you need a slider hitch for a 6.5-ft bed?
No, you don’t necessarily need a slider hitch for a 6.5-ft bed, but most short bed trucks require it. There is not necessarily a standard truck bed size for a 5th wheel. It depends on the trailer width. Measure the trailer across and divide by 2. If that distance is less than the distance between the truck cab and the coupling point, a slider hitch will be needed.