Select Your Vehicle
view cartView Cart
Only 11 Hours 53 Minutes Remaining

Fifth Wheel King Pin > Air-Ride > Fixed > Youngs Welding > Youngs - M > 21000 lbs GTW > Ultra-Fab Products

Ultra-Fab Trailair Air Ride 5th Wheel King Pin - Youngs Welding (Medium Box) - 21,000 lbs

Ultra-Fab Products Fifth Wheel King Pin

Code:   UF35-946217



Shipping Special

Shipping Weight: 184 pounds

Ships via truck freight, additional fees apply.
Ship to:


Ultra-Fab Products Fifth Wheel King Pin - UF35-946217

Experience smooth, stable towing with your fifth-wheel trailer by replacing your ordinary pin box with an air-ride-equipped model. The scissoring action of the coupler allows the interior air bag to absorb road shock so that you won't feel it.


  • Air ride pin box replaces standard pin box on your 5th-wheel trailer to enhance performance
    • Cushions and absorbs road shock
    • Improves handling and overall ride
    • Limits strain on truck and trailer frames
  • Scissor action allows pin box to compress, compensating for jarring and bounce
    • Internal air bag absorbs the road shock
    • Built-in spring ensures that pin box rebounds - keeps air bag from breaking down
  • Direct replacement for OEM pin box
  • King pin connects to any 5th-wheel trailer hitch
  • Sturdy steel construction


  • Designed to replace the following pin boxes:
    • Youngs Welding - medium box
  • Weight capacity: 21,000 lbs
  • 1-Year warranty

Note: Not for use with any type of gooseneck adapter.

Eliminate the bounce from your ride with the Trailair air ride coupler. The unique scissoring action of the pin box ensures that road shock is absorbed, preventing the harsh, rigid ride that you typically encounter while towing your fifth-wheel trailer. Not only does this improve your overall towing experience, but it also helps maintain a sound, well-functioning system. Less bounce and jarring means less stress on your truck, trailer and hitch.

Trailair Air Ride Coupler

How the Trailair Air Ride Works

When you encounter uneven terrain on your trip or hit a pothole on the highway, the Trailair pin box compresses, transferring the road shock to its internal air bag. A built-in air spring ensures that this compression occurs in a controlled fashion so that the air bag doesn't burst. It also causes the pin box to appropriately rebound, positioning it so that it's ready for the next bump in the road.

35-946217 UltraFab Trail Air Kingpin Box - M18


Ask the Experts about this Ultra-Fab Products Fifth Wheel King Pin
Expert Answers about Ultra-Fab Trailair Air Ride 5th Wheel King Pin - Youngs Welding (Medium Box) - 21,000 lbs - UF35-946217                                       Do you have a question about this Fifth Wheel King Pin?

  • Sidewinder or Extended Pin Box to Replace Youngs Welding 8 X 8 Straight Vertical Pin Box
  • For somebody in your situation, a Sidewinder would typically be my recommendation. However, there is not an extended pin box or Sidewinder available for a Young's Welding 8x8 pin box. If you have a 6-1/2 inch truck bed, using a sliding fifth hitch might gain you the clearance you need. Otherwise, you'll need a truck with an 8 foot bed for the proper clearance. I sure wish I had better news for you. The Ultra-Fab Trailair pin box you referenced is designed to fit a Young's Welding...
    view full answer...

Info for this part was:

Expert Research:
Michael L

Written by:
Lindsey S

At we provide the best information available about the products we sell. We take the quality of our information seriously so that you can get the right part the first time. Let us know if anything is missing or if you have any questions.

Stay Connected

Subscribe to email newsletter


privacy - we don't send unsolicited email

Only 11 Hours 53 Minutes Remaining reviews

All images, layout and content copyright