The pin box is the kingpin assembly that connects your fifth wheel trailer to the hitch in your truck bed. Upgrading or replacing your pin box can improve ride quality, reduce chucking (that jarring back-and-forth when stopping and starting), and even allow you to tow with a short-bed truck without a slider hitch.

Pin box types

• Standard pin boxes: Factory-installed rigid boxes. They work but transmit every bump and jolt to the truck.
• Air ride pin boxes: Use air cylinders or bags to absorb vertical movement. Best for smoothing out rough roads.
• Cushioned pin boxes: Use rubber or polymer cushions to reduce chucking and road shock without air components.
• Extended pin boxes: Move the kingpin farther back, creating more clearance between the trailer and truck cab for short-bed trucks.

Key specifications

• Pin weight capacity: Must meet or exceed your fifth wheel's pin weight (listed on the trailer's weight sticker).
• Pin box width: Measure your current box—common widths are about 10 to 13 inches.
• Kingpin: Standard 2-inch kingpin fits most fifth wheel hitches.

Upgrading your pin box is one of the best investments for towing comfort. Contact us if you need help selecting the right capacity and style for your trailer.

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