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  1. Fifth Wheel King Pin
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Trailair Air Ride 5th Wheel King Pin - Steelco/Davis, Venture - 21,000 lbs

Trailair Air Ride 5th Wheel King Pin - Steelco/Davis, Venture - 21,000 lbs

Item # UF35-946211
Our Price: $1,299.35
You Save: $161.60
Fifth Wheel King Pin
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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. 1-800-940-8924 to order Lippert fifth wheel king pin part number UF35-946211 or order online at Free expert support on all Lippert products. Great prices and Fastest Shipping for Trailair Air Ride 5th Wheel King Pin - Steelco/Davis, Venture - 21,000 lbs. Fifth Wheel King Pin reviews from real customers.
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  • Reviews (148)
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Lippert Fifth Wheel King Pin - UF35-946211

  • Venture CJ20515
  • Venture CJ20517
  • Steelco-Davis PB02
  • Steelco-Davis PB02W
  • Upgraded Pin Box
  • Lippert
  • 21000 lbs GTW
  • Absorbs Road Shock and Reduces Chucking
  • Fixed Turret

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:
    • Venture CJ20515 and CJ20517
    • Steelco/Davis PB02,PB02W
  • Weight capacity: 21,000 lbs
  • 1-Year warranty


  • Not for use with any type of gooseneck adapter
  • Because of the size of this item, it ships via truck freight

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.

155925 Lippert Components (LCI) Trail Air Kingpin Box - L03

Replaces 35-946211 UltraFab Trail Air Kingpin Box - L03

Customer Reviews

Trailair Air Ride 5th Wheel King Pin - Steelco/Davis, Venture - 21,000 lbs - UF35-946211

Average Customer Rating:  4.8 out of 5 stars   (148 Customer Reviews)

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.


Smooths out the ride greatly, really pleased with so far. I removed the Air chuck and installed a tee with Gauge and air chuck makes it easy to monitor air pressure before traveling, one should note that these do bleed pressure down in few weeks that is pretty much normal for air bags of this type. I have a Dewalt cordless mini compressor and it works great to quickly & quietly pressurize before trip. I usually set my at 65 PSI


I think that this is just what the doctor ordered. I have not installed it yet, but this looks very much like what I need for my trailer!



This product performs as advertised, I am very happy with it . It helps to make my fifth wheel in one piece on the extremely rough roads in the north east. I feel much safer with the cushion that the pin box provides.



by: 05/08/2023

We're so anxious to try out our new Curt TrailAir.
Installation went smoothly, it looks great.
We can hardly wait to experience the ride!


the fit was perfert. as you can see from the pictures is attached, i drilled a hole in the top to drain water that collects. i fabercated a cover to fit over the opening.


Swapped out the MorRyde cushioned pin box. This Air Ride is awesome


Fit my 2018 Velano 39ft 5th wheel like a glove. Less than 1/2 hour by myself, with forks on my compact tractor for lifting, and it was installed. Ride is so much better than prior roto flex box


Havent used it yet, but M19 pin box is well made. As usual, etrailer shipped it quick and it arrived with zero defects. Ill update after first use


Freight co delivery estimated for Friday, arrived today. (Tuesday). Borrowed a tractor, dropped the old and lifted this monster into place. 12- 15/16 bolts (originally) 18 hole mount. Not sure if the height is correct for the bed, but will adjust it down if after the rubber bumper is inflated, if it doesn’t sit level. The bolt pattern was correct. better get help! From dropping the MFG lippert, to getting the thing lifted an bolts snugged up, about 45min. Will take a bit longer to attach the deadman switch and electrical box. Well crafted, definitely heavy. This should save my truck n RV from porpoising damage as I’m going over Bridges and bad roads.


I have used this product for a year now, I really like it , would not take my money back. Sure made my fifth wheel more fun to pull
Crossing bridges don't bounce me around like it did with the old standard pin box


Our fifth wheel experienced pin box cross frame cracking while on a trip. After having it properly repaired I decided to invest in the Trail-air pin box to alleviate the shock and harsh pounding from our lousy roads. I purchased from and installed it myself. Being only a 29 foot 5th wheel the tounge weight is low so after experimenting with pressures I run 40 psi in it and it flexes when hitting bumps or dips taking the stress off the trailer. Tows like a dream. Knowing what I know now I would have bought and installed it when I bought the 5th wheel and saved a repair during a trip. It is expensive but well worth it.


I am well pleased with the ride improvement this king pin provides. It greatly reduces the chucking and makes for a much more enjoyable journey.


I’ll start from the second I ordered this online. Confirmation email, then within days a shipping confirmation. When I ordered my shipping said 2 weeks out for delivery. I got the item in 9 days. The communication from the freight service was top notch. Unlike, some reviews the item was in great condition when it arrived. On a pallet in a box. No complaints. The driver even let me back up to his lift gate and help me slide the item into my truck for easier install. I had previously removed the factory hitch box prior to arrival so when the upgraded item arrived I was ready for install. Took about an hour to line everything up. Used a jack in the truck bed to help lift item where I needed it. I haven’t towed with it yet, that’ll be next week. But it looks beastly and like it’ll be a much more comfortable ride for me and my truck. Very happy so far, will leave an updated review after an out of state trip next weekend. etrailer was great. First item Ive ordered from you all but I’ll be back. Thank you!! Happy customer!!


Have put around 10K miles on the hitch so far and it has performed well. An extra step in the pre-departure checklist to check the airbag pressure/ride height, but it is worth it as it greatly reduces the jarring from pot holes and abrupt changes in road surface. Installation was easy; perfect fit.


Smooths out the porpoising when traveling over rough roads and at uneven bridge abuttments.


I purchased this Lippert Air Ride hitch for my 40 foot Genesis Supreme trailer and wish I had bought it 2 years ago and installed it. What a difference is has made both in the trailer when towing as well as the difference in my truck while pulling it down the road. eTrailer had the best price and fast shipping. They as well helped me with verifying the right part number that works with my trailer. I purchase many parts and accessories from eTrailer and will continue to purchase from them in the future.


The king pin has eliminated about 80% of the chucking. I pull 16k fiver. I am very happy with it. Related I always use etrailer for my parts purchase. One time I was stranded near Disneyland. I needed shackle. They had me triple check for correct part and rushed delivery. These guys are the real deal.


Best upgrade to the 5th wheel you can do. Our first cross country trip and I-40 beat the snot out of us on all the bridge transitions with the stock pin box. Immediately ordered this unit and now it’s like the trailer is floating behind us. I run 65 psi in the airbag. Solid unit and easy installation.


Exact fit replacement for cheap Keystone OEM part. Fit was so exact, I installed it by myself. Arrived earlier than expected. I hope this will reduce the chucking and smooth out the pull of a 16K RV trailer. I did have to purchase additional bolt sets from my local Home Depot (OEM was 12 sets, this is 18 sets 5/8-11 x 2in Grade 8 with flat and lock washers all torqued to 180 ft lbs).


I just completed a 2800 mile trip after installing the Trail Air Air Ride pin box on my Solitude 5th wheel. I was able to install it myself from the bed of my pickup using a hydraulic bottle jack to lift it into position.

I previously made the same trip with the factory installed MORryde Cushioned Pin Box and the Trail Air provides a greatly improved ride. With the MORryde, I encountered several sections of concrete highway that set up a front-to-back oscillation which persisted across many miles. I didn't have that issue with the Trail Air.

I didn't order the Flex Air model that also included the flexible block because I was concerned the added height of that pin box would have been a problem. However, after installing the non-flex Trail Air I've found that the other one would have also worked out if I lowered my truck hitch an inch or two.

Also worth noting, this pin box is four inches shorter than the 1621 MORryde it replaced. However with a long bed truck I have no clearance issues and can still lower the tailgate when hitched up.


Good looking product. Mounted it on a Montana 40ft 5th wheel. It arrived 2 weeks ahead of schedule. It was easy to install. I did have to grind the corners of the trailer frame bracket as the jaw hinge wouldn’t allow the bolt holes to line up. Once the corners were ground, everything lined up perfectly. It only took my son and I to pick up the pin box and once the first bolt was in, it was simple and easy to do the rest. There are 3 things to complain about. 1. The position of the air valve sucks. Really hard to get at. 2. The mark on the shock for proper inflation is not marked well. Had to get on hands and knees with a flashlight to actually see it. It was suppose to be bright yellow, it’s black, same as the shock. My 3rd complaint would be the fact that I had to drill 3 holes into the pin box to reattach the brake safety cable and the electrical wire box. The biggest positive thing is, is how much of a difference it has made in the ride quality for not only with the trailer but the truck as well. Soooo much smoother than the original pin box. Would I buy another one? You better believe I would. Wondering why I didn’t buy it sooner. Won’t have another 5th wheel without it.


Obviously a quality product made with quality materials. As you can see in the photo I placed the bottom bolts in the bottom hole. Problem is the bottom steel place is very close to the hardware so I had to have the bolt facing outward on the two bottom forward bolts. Don’t like torquing bolt heads but it worked. This is being very nit picky Torqued to 160 ft lbs.


Have not did a road test yet but it’s installed.
Way heavier than factory. I have talked to many that have this and like it.
Helps reduce chucking back and forth movement. Nothing will be solve all if you are on a rough road you will feel it.
No hitch will eliminate.
Was fairly easy to install you will need help to lift. I used the tailgate on the truck and backed under and used blocking to get in place. I installed pretty much myself. My wife help some with aligning the bolts.


This is an outstanding pin box. It makes our trailer pull really nice. I know everyone says "I didn't even know I was towing anything" which is usually not the case, however with this, it really was like nothing was/is behind me. I highly recommend this product.


I love this AirRide by Trail-air. It provides an incredibly smooth ride on the road. You can adjust the amount of air for your ride, the Schrader valve is right on top of the unit and easy to access. My Trail air installed easily on my Forest River Sandpiper 372LOK mid bunk, especially with help from my Dad. This Trailair solved a big problem for me. I needed an extra couple of inches space between my 2018 Ford Super Duty DRW and the coach. My truck came with the Ford factory-installed Reese 27K hitch and I needed more clearance to allow the tailgate to drop without touching the coach. The kingpin on the Trailair sits at least 2” forward of the factory kingpin and provided that desperately needed space. It really makes for smooth and quiet ride !
etrailer folks were very helpful. The first unit was damaged by the freight company and when I notified them, etrailer sent another unit quickly. I will buy from etrailer whenever I can..

Show More Reviews

See what our Experts say about this Lippert Fifth Wheel King Pin

  • Upgraded Pin Box for Venture CJ20517 Pin Box
    We do have a confirmed fit with the Trailair Air Ride 5th Wheel King Pin to replace your Venture. The part # UF35-946211 is a direct bolt-on replacement rated to 21,000-lbs.
    view full answer...
  • Can Steelco/Davis PB02,PB02W Pin Box Be Replaced By Reese Sidewinder Pin Box
    The only replacement pin box for your Steelco/Davis PB02,PB02W is the Trailair Air Ride 5th Wheel King Pin # UF35-946211 but I still have a solution for you if the desire is to eliminate the need to get in and out of the truck to use a manual sliding 5th wheel hitch. The Demco Autoslide 5th Wheel Trailer Hitch # DM8550034 is a great way to add ease of use to your towing setup. This uses an autosliding feature that means you can remain in your cab your entire trip - even when making sharp...
    view full answer...
  • Trailair Pin Box Replacement Recommendation for 2008 Rockwood Signature 8287SS
    For your CJ20517 pin box we have the Trailair Pin Box part # UF35-946211 which is a confirmed fit and would work well.
    view full answer...
  • What is the Difference Between Trailair Pin Boxes UF35-946211 and UF35-946219
    The difference between the two Trailair Pin Boxes that you referenced are the pin boxes they are designed to replace on a trailer. The part # UF35-946211 is designed to fit the Venture CJ20515 and CJ20517 and Steelco/Davis PB02,PB02W whereas the part # UF35-946219 is designed to replace the Steelco/Davis PB01 and Venture CJ13515, CJ13517 and Short. Either would be fine with your long bed truck, it would just be a matter of picking out the right one to replace the pin box on your trailer.
    view full answer...
  • Air Ride Pin Box Recommendation for a 2005 Holiday Rambler Savoy
    If your 2005 Holiday Rambler has a Lippert 1621 pin box like you mentioned then for an air ride pin box you would want the # LC328492 which is a Flex Air cushioned pin box that would work well for you. On the pin box of your trailer there should be a sticker or plate that has the pin box model info. You will need to verify that you have a 1621 pin box before ordering.
    view full answer...
  • Air Ride Pinbox Compatible With a Steelco/Davis Pin Box PB02 or PB02W?
    There is not a Flex Air pin box fit for your Steelco/Davis PB02 or PB02W pin box. There is similar option available in the Trailair Air Ride 5th Wheel King Pin - Steelco/Davis, Venture - 21,000 lbs # UF35-946211 that is a fit. You won't have the additional pivot with cushioning at that pivot found in the Flex Air, but you will still have the air ride adjustable replacement for your current pin box.
    view full answer...
  • 2012 Jaco Eagle 31.5 RLTS Cushioned Pin Box Replacement
    Based on dimensions we've had sent to Lippert we know that the Trailair part # UF35-946211 can fit in place of your Dexter AF7926 pin box to provide you with a cushioned replacement.
    view full answer...
  • Selecting Replacement Trailair Air Ride 5th Wheel King Pin for 2007 Jayco 5th Wheel
    Selection of a Trailair Air Ride 5th Wheel King Pin to replace your existing pin box is best made by using the original pin box part number. This should appear on its safety sticker. If this is not available the trailer manufacturer should be able to tell you the pin box they installed if you give them the VIN. The linked article includes a cross reference of compatible air ride pin boxes; simply check for your OEM pin box number to see if a suitable air ride unit is offered. If this is...
    view full answer...
  • Reese Goose Box Availability to Replace a Venture CJ20517 on an 03 Holiday Rambler Alumascape
    The number you found on the side of your current king pin will mean you have a Venture CJ20517. This does complicate things a bit as this style is not very common and the only option we have that will fit it is the Lippert Trailair Air Ride # UF35-946211. However, this will fit a standard 5th wheel hitch and wont really help with your situation. The only other option we will have will be the Andersen Ranch Hitch Universal 5th-Wheel-to-Gooseneck Coupler Adapter # AM3100 for a truck with...
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  • How to Determine Fifth Wheel Pin Box Model
    If you are unable to contact your trailer's manufacturer with your VIN to find the factory pin box model number there are some steps you can take which will allow you to determine what pin box model you have so you can purchase a new FlexAir. To do this you will need to follow the steps in the linked help article, which I will go over with you. Start by selecting your pin box style like in the accompanying photo (which you will also find in the help article). You will then need to use...
    view full answer...
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Info for this part was:

Employee Lindsey S
Written by:
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Employee Jeff D
Installed by:
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Employee Jameson C
Expert Research:
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Employee Kathleen M
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