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Trailair Flex Air 5th Wheel Pin Box - Lippert 1621 - 21,000 lbs

Trailair Flex Air 5th Wheel Pin Box - Lippert 1621 - 21,000 lbs

Item # LC369535

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Fifth Wheel King Pin

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Shipping Weight: 232 lbs

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LC369535 - 21000 lbs GTW Lippert Components Pin Box Upgrade
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  • 1621
  • Lippert
  • Reduces Bounce and Jarring
  • 21000 lbs GTW
  • Pin Box Upgrade
  • Lippert Components
  • Fixed Turret
  • Cushioned
Flex Air drastically reduces chucking, absorbs road shock, and minimizes bounce. The internal air bag and built-in strut work with the rubberized pivoting head to achieve a dramatically smoother ride. Replaces Lippert 1621 pin boxes. Call 800-298-8924 to order Lippert Components fifth wheel king pin part number LC369535 or order online at etrailer.com. Free expert support on all Lippert Components products. Guaranteed Lowest Price and Fastest Shipping for Trailair Flex Air 5th Wheel Pin Box - Lippert 1621 - 21,000 lbs. Fifth Wheel King Pin reviews from real customers.


  • All Info
  • Reviews (2)
  • Q & A (55)
  • Videos (1)
  • Photos
  • Why etrailer?

Lippert Components Fifth Wheel King Pin - LC369535

Flex Air drastically reduces chucking, absorbs road shock, and minimizes bounce. The internal air bag and built-in strut work with the rubberized pivoting head to achieve a dramatically smoother ride. Replaces Lippert 1621 pin boxes.


Features:

  • Air ride pin box with a pivoting head replaces standard pin box on your 5th-wheel trailer to cushion your ride, improve handling, and limit strain on truck and trailer
    • Drastically reduces chucking
    • Virtually eliminates bounce and jarring
  • Internal air bag absorbs road shock
    • Scissor-like motion allows pin box to compress, compensating for jarring and bounce
    • Built-in shock ensures that pin box rebounds - keeps air bag from breaking down
  • Pivoting head limits chucking by allowing controlled movement of the king pin within your hitch
  • Rubber compound built into the head absorbs road shock
    • Reduces wear and tear on trailer
  • Black powder coat provides rust resistance
  • Sturdy steel construction
  • King pin connects to any 5th-wheel trailer hitch
  • Bolt-on installation with no assembly required
  • Made in the USA


Specs:

  • Designed to replace Lippert 1621 5th-wheel pin box
  • Weight capacity: 21,000 lbs
  • Distance from bottom of king pin to top of box: 19-9/16"
  • Distance from center of king pin to back of box: 29-9/16"
  • 1-Year limited warranty


Notes:

  • Do not use the Trailair Flex Air pin box with any type of gooseneck adapter.
  • Because of the size of this item, it ships via truck freight.

Getting there is half the fun, right? Not if you're being bumped, jerked, jammed, and pushed around from the chucking, road shock, and bounce that occurs as you tow your fifth-wheel trailer or RV. And imagine the costly wear and tear on your trailer as it endures that rocky ride.


Put the fun back into your trip and ease the stress on your trailer by replacing your factory pin box with the Trailair Flex Air pin box. The internal air bag and built-in shock work together to cushion your ride, improve handling, and limit strain on both your truck and your trailer. But what sets the Flex Air apart from other air ride pin boxes is the addition of a pivoting head. This head, along with its built-in rubber compound, provides additional cushion, absorbs road shock, and reduces chucking for a significantly improved ride.


Rubber Compound and Internal Air Bag Absorb Road Shock

Lippert Flex Air pin box has a rubberized pivoting head

A heavy-duty rubber compound is built into the head assembly of the Flex Air pin box. This rubber is the first defense against road shock. It helps to absorb the bumps and vibrations experienced when towing a fifth-wheel trailer over rough roads. Standard pin boxes without any type of shock absorption transfer road shock to your trailer, resulting in potential damage to the trailer and an overall bumpy ride. The shock-absorbing rubber inside the Flex Air takes the beating so there's less wear and tear on your trailer or RV and you get a smoother ride.


Lippert Flex Air pin box has a shock and air bag

Because the rubber may not be able to absorb all of the road shock that you experience, the Flex Air also implements air ride technology to virtually eliminate shock. When you encounter uneven terrain on your trip or hit a pothole on the highway, the Flex Air pin box compresses vertically, similar to how a pair of scissor blades closes in on each other. This compression transfers the road shock and vibrations to the internal air bag, saving your fifth-wheel hitch, trailer, and tow vehicle frame from enduring a rocky ride.


A built-in strut, or shock, controls the Flex Air's compression so that the internal air bag doesn't burst. The strut also causes the pin box to appropriately rebound without any bounce, and positions it to be ready for the next bump in the road.


Pivoting Head Reduces Chucking

Lippert Flex Air pin box has a pivoting head that reduces chucking

The pivoting head on Flex Air allows for controlled back and forth movement of the king pin to reduce the uncomfortable jarring known as chucking. Unlike a rigid pin box that has little give at the point where the trailer and the hitch are connected, the Flex Air can pivot slightly to compensate for those times that your trailer suddenly pushes or pulls on your tow vehicle. Because the pin box head - not the king pin itself - is moving, the chucking that often occurs when the king pin jerks around inside the hitch is significantly reduced.


Simple Setup and Installation

First, simply remove your existing Lippert 1621 pin box from your trailer. The Flex Air uses the same bolts that held on your original pin box so no additional hardware is required for installation. Plus, the Flex Air pin box comes out of the box ready to be put on your trailer, so no assembly is needed. Because the Flex Air is quite heavy, you should put it on an elevated surface or have a friend help you support its weight during installation.


The internal air bag should be inflated after the Flex Air pin box has been mounted on your trailer. Using the air intake valve, inflate the air bag until the outer cylinder of the shock rises high enough to fully expose the yellow inflation indicator sticker.



369535 Lippert Components (LCI) Flexair by Trail Air Fifth Wheel Kingpin Box for Lippert 1621 - 21,000 lbs



LC369535 Installation InstructionsInstallation Details LC369535 Installation instructions

This Product Fits The Following Vehicles

2019 - 2019 Forest River Sabre Fifth Wheel 36BHQ

2016 - 2016 Jayco Pinnacle Fifth Wheel 36KPTS Luxury




Video of Trailair Flex Air 5th Wheel Pin Box - Lippert 1621 - 21,000 lbs


Videos are provided as a guide only. Refer to manufacturer installation instructions and specs for complete information.




Video Transcript for Lippert Components Fifth Wheel King Pin - Pin Box Upgrade - LC369535 Review

Speaker 1: Today, we're going to be taking a look the Trailair FlexAir fifth wheel pin box. This is going to be a really nice addition to your fifth wheel trailer because it's going to drastically reduce chucking and absorb road shock. It's also going to minimize bounce with your fifth wheel trailer. And the internal air bag and built-in strut work together with the rubberized pivoting head to achieve a dramatically smoother ride.This is going to replace the standard pin box on your fifth wheel trailer from Lippert. Lippert 1621 or one-six-two-one. And it's going to be designed, again, to ensure that smoother ride with the rubber compound built into the head.

If I turn the table here, I'll give you a little bit better look at that. So it's basically going to be a rubber block built into that head assembly and that's going to absorb a lot of that initial road shock. And then this plate is also going to pivot, so it's going to allow controlled movement of that head assembly within your hitch so it's going to reduce that chucking that you normally find with your fifth wheel trailer. Any road shock that's not absorbed between those two will be handled by the air bag that is built in. That's going to virtually eliminate any bouncing or shock that you would have from that trailer going down the road.

There's also this shock built in so that it . it's going to make sure that that air bag returns to its natural shape. And it's going to eliminate wear overtime from that air bag.This is going to have a scissor-like motion in the pin box, so it's going to compress and come back to normal. And that's going to compensate for that jarring and bouncing. And, again, that shock helps to keep that bag from breaking down over time.Now, by eliminating all that shock and jarring from the road, not only is that going to make your ride a lot more comfortable, but it's also going make sure that your truck and trailer last a lot longer if it's not having to deal with all that shock and trauma from the road going ...

while you're towing, it's going to make all those suspension components last a lot longer.And this is going to have a black powder coat that covers the entire thing, and that's going to prevent rust. It does have a sturdy steel construction and the king pin connects to any standard fifth wheel trailer. One thing to note with this is that it is not designed to work with any type of gooseneck adaptor, so keep that in mind.The bolt on installation is going to be really easy and there's no assembly required with this. It is, again, designed to replace the Lippert 1621 fifth wheel pin box. The weight capacity is 21,000 pounds.

And another thing to keep in mind with this is that is going to be very heavy. So whenever you install this, make sure you have a couple extra hands to get this on your fifth wheel trailer.That's going to do it for our look at the Trailair Flex Air fifth wheel Pin box.


Customer Reviews

Trailair Flex Air 5th Wheel Pin Box - Lippert 1621 - 21,000 lbs - LC369535

Average Customer Rating:  4.5 out of 5 stars   (2 Customer Reviews)

Flex Air drastically reduces chucking, absorbs road shock, and minimizes bounce. The internal air bag and built-in strut work with the rubberized pivoting head to achieve a dramatically smoother ride. Replaces Lippert 1621 pin boxes.

- LC369535
by:

product smooth's out ride over our great highways (cattle paths) here locally. only issue I have is that the pin box once tightened down into the original bolt holes is leaning to one side and is noticeable in the rear view mirror as I haul. 562437



- LC369535
by:

Great product for any fifth wheel! Really smoothes out the ride for both the truck and trailer. Easy bolt on install! All RVs should come with one of these! 572226


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Ask the Experts about this Lippert Components Fifth Wheel King Pin
Do you have a question about this Fifth Wheel King Pin?


  • Comparing Trailair Flex Air 5th Wheel Pin Boxes For Lippert 1621 Pin Box Replacement
  • The difference between the Trailair Flex Air 5th Wheel Pin Box - Lippert 1621 - 18,000 lbs # LC328492 and the Trailair Flex Air 5th Wheel Pin Box - Lippert 1621 - 21,000 lbs # LC369535 is only in the weight capacity. The air spring and shocks are the same on the unit designed for 21,000 lbs, so just the mounts on the trailer and the pin box itself is stronger. The Lippert 1621 pin box allows for either weight, so I recommend the one that is most compatible with the trailer GVWR. Either...
    view full answer...

  • What is the Difference Between the Trailair Air Ride and Flex Air for a Lippert 1621 Pin Box
  • Even though both the Trailair Air Ride # LC158778 and the Trailair Flex Air # LC369535 look similar and incorporate the air bag and shock to help improve your towing experience, the Flex Air has a few upgrades that the Air Ride does not have. The 2 things that separate these 2 5th wheel pin boxes is that the Flex Air has a rubber compound that is built into the head assembly which really helps to absorb road shock. The Flex Air also has a pivoting head which gives you controlled back...
    view full answer...

  • Correct Trailair Replacement for Lippert 1621 Pin Box
  • I spoke with a representative of Lippert who told me that you have a Lippert 1621 pin box with a 15,500 lbs capacity. For a Trailair you could use Trailair Flex Air 5th Wheel Pin Box # LC328492. These pin boxes are going to substantially reduce the amount of jarring and chucking you experience by absorbing the road shock with an air bag. It is a simple bolt-on design and has a capacity of 18,000 lbs, though Trailair # LC369535 would also work for you and has a capacity of 21,000 lbs....
    view full answer...

  • Benefit of Using 5th Wheel Pin Box Rated for More Than Trailer Actual Weight
  • The Lippert TrailAir Flex Air 5th Wheel Pin Boxes # LC328492 and # LC369535 are both bolt-on replacements for the model 1621 OEM pin box. Their difference, as you noted, is in their rated weight capacities; 18K for # LC328492 and 21K for # LC369535. Either one will be fine for use with a compatible trailer with a GVWR of 16,500-lbs. But yes, safety margin in the form of extra capacity is a good thing. The relatively low incremental cost for the 21K pin box over the 18K makes a pretty...
    view full answer...

  • Trailair Air Ride 5th Wheel Pin Box Replacement Parts
  • The bushings on your 21,000 lbe Trailair Air Ride Coupler are integrated into the Replacement Shock for Trailair Air Ride and Flex Air 5th Wheel King Pins - Qty 1 # LC177223. If you have the # LC369535, then you will want the Replacement Air Bag For Trailair 5th Wheel Pin Boxes - Qty 1 # LC432404 instead. If you also need a new valve, you can use the Replacement Pin Box Tank Valve for Lippert or UltraFab TrailAir Pin Boxes # LC156740.
    view full answer...

  • Best Pin Box Upgrade Recommendation for 2017 Grand Design Momentum with a 1621 Pin Box
  • For your 2017 Grand Design Momentum that has a Lippert 1621 pin box the best upgrade we have is the Trailair Flexair part # LC328492. This has cushioning vertically and a pivoting king pin plate that allows for cushioning front to back as well. This will give you a noticeable smoother ride quality than what you currently have.
    view full answer...

  • Replacement Trailair Flex Air 5th Wheel Pin Box for Lippert 1621
  • No, the Lippert 1621 will not have any issues with an 8' truck bed. The trailer will just sit a little further back. I spoke to my contact at Lippert and they stated that the general rule of thumb for a truck with an 8' bed would be to use a short/medium pin box. However, this could in turn create an interference issue with the tailgate as you mentioned. It will also put more stress on the trailer's chassis. Therefore, I recommend replacing the Lippert 1621 pin box that came on your trailer...
    view full answer...

  • Trailair Flex Air Pin Box Recommendation to Replace 1621 Pin Box
  • We have two Flex Air pin boxes that are a confirmed fit for replacing a Lippert 1621 pin box like what you have. We have the part # LC328492 which has an 18k capacity and the part # LC369535 which has a 21k capacity. This will work well with your 2017 Ram 2500 that has air autoleveling suspension. They would not fight each other or anything.
    view full answer...

  • Replacement Pin Box for a 2012 Jayco Eagle 5th Wheel Trailer
  • I spoke to my contact at Lippert and they informed that they did not start keeping a record of pin boxes until 2013. Therefore, the only way you are going to be able to identify what bolt pattern you have is by measuring the mounting holes using the attached photo. The most common bolt pattern is a 1621 which measures as follows: 2a: 7-7/8" 2b: 2" 2c: N/A 2d: 5/8" 2e: 15/16" 2f: 6 3a: 17-3/4" 3b: 25-5/8" 3c: 12" If your measurements match these then the correct Trailair Flex...
    view full answer...

  • How Much Does the Lippert 1621 Trailair Flex Air Pin Box Weigh 369535
  • The Trailair Flex Air 5th Wheel Pin Box part # LC369535 that you referenced weighs around 230 lbs.
    view full answer...

  • Comparing the 18K and 21K Lippert 1621 Flex Air 5th Wheel Pin Boxes
  • The Trailair Flex Air 5th Wheel Pin Box part # LC369535 which is rated for 21,000 lbs is constructed of a thicker metal and also has beefier welds when compared to the Trailair Flex Air 5th Wheel Pin Box part # LC328492 which is rated for 18,000 lbs. The air bag and shock that is used in each of them are the same. The thicker metal and welds are what gives the former a higher weight capacity. The best option for you would be the one that meets the GVWR of your trailer though you could go...
    view full answer...

  • Recommended Replacement Pin Box for Lippert 182209 1621 on 2010 KZ Durango LX
  • I reached out to my contact at Lippert and you do have the 1621 pin box on your 2010 KZ Durango LX. If you are looking for a cushioned pin box, I recommend the Trailair Flex Air 5th Wheel Pin Box - Lippert 1621 - 18,000 lbs # LC328492 or the 21,000 lb # LC369535. Either of these will work well and they not only have the air ride but also have a rubber compound and moving head to be the fist defense against road shock and chucking. If you desire greater turning clearance, then the 5th...
    view full answer...

  • Replacement Air Bag for a TrailAir 5th Wheel Pin Box
  • There are numerous TrailAir pin boxes that could take replacement air spring # LC432404. Check your pin box for a sticker that has any sort of part number on it and that will tell us which one you have. Air bag # LC432404 is designed for the following pin boxes: Air Ride - Lippert 1621 with 21,000-lb capacity # LC158778 Air Ride - Lippert 0719 with 18,000-lb capacity # LC179879 Flex Air - Lippert 1621 with 18,000-lb capacity # LC328492 Flex Air - Lippert 1621 with 21,000-lb capacity...
    view full answer...

  • Air Ride 5th Wheel Pin Box for 5th Wheel Trailer with Lippert 1621HD Pin Box
  • The Trailair and Trailair Flex Air pin boxes offer fantastic ride quality compared to standard pin boxes and would be the way I would go. But it all depends on the manufacturer and model number of your trailer's pin box. This information should be on a sticker or plate on the pin box itself. If that information is not available there are some measurements you can take to identify it. Use the help article I linked below that explains the necessary measurements if you need to. Once you...
    view full answer...

  • Replacement Air Bag for Lippert Trailair Pin Box
  • There is a replacement air bag # LC432404 for Trailair pin boxes that you could use. The replacement air bag will work with Trailair # LC158778, # LC179879, # LC328492, and # LC369535.
    view full answer...

  • Do Flex Air Pin Boxes Have Pin Weight Capacities
  • I spoke with my contact at Lippert about the Flex Air part # LC328492 and he did not have a pin weight figure for the pin box. He said the box is rated for towing up to a 18,000 lb trailer. The Flex Air # LC369535 then has a 21k overall capacity.
    view full answer...

  • How to Determine if a Flex Air Pin Box Will Clear Taller Bed Rails on a 2017 Ford F-350 Super Duty
  • We haven't heard any reports of that specific combination having issues, but we do know that there have been issues with newer Ford trucks like your 2017 Ford F-350 Super Duty. The problem with clearance will not have to do with the Flex Air as much as it will have to do with your trailer. Basically you will want to make sure that you can adjust your pin box and 5th wheel hitch so that you have 5" - 6" of bed rail to trailer height clearance, and that the nearest point of your trailer...
    view full answer...

  • Flex Air or Air Ride Pin Box with Companion 5th Wheel Hitch
  • One thing to ensure is that your Companion hitch is at the tallest height setting. This could provide an easy solution for connecting your king pin. I spoke to my contact at B&W, who confirmed that your Companion is compatible with both pin boxes. I also spoke with Trailair, who said that the Flex Air would provide you with over 6 inches in additional height. The Flex Air would also be the best option for eliminating chucking and creating a smoother ride. We offer the Flex Air pin...
    view full answer...

  • New Decals for a Trailair L05
  • Thanks for the photos. We do have the Replacement Decal for Lippert Components Trailair 5th Wheel Pin Box - GVW 21,000 # LC157285. We also have the Replacement Decal for Trailair 5th Wheel Long Style Pin Box - Driver's Side # LC157268. The warning decals we do not have available. I've not seen the bike rack mount in that location and it seems it would greatly reduce turning clearances so it must be for just storage when not in use.
    view full answer...

  • Cushioned Pin Box Replacement for Lippert 1621 on 2017 Grand Design Reflection 303RLS
  • The available replacement 5th wheel king pins that you can use in place of your Lippert 1621 are shown on the linked page. All of these are engineered to reduce jarring and bounce and all are direct bolt-on installations. All come fully-assembled. The best ride quality will come from the Trailair Flex Air models, the 18K # LC328492 and the 21K model # LC369535. Both use a 3-part combination of air cushion, gas strut and rubberized pivoting head. These features reduce road shock, bounce...
    view full answer...

  • Recommended Trailair Pin Box for Lippert 1621 Pin Box on Trailer
  • It sounds like you are looking at the Trailair Air Ride 5th Wheel Pin Box # LC158778 and the Trailair Flex Air # LC369535 (which replaced the now discontinued Tri-Glide) for your Dutchmen Voltage 5th Wheel Trailer. Both of these units are confirmed to fit your trailer that is equipped with the Lippert 1621 pin box. Both of these pin boxes feature an internal air bag and strut to absorb road shock and smooth out your ride, but the Flex Air does offer some upgrades over the standard Air...
    view full answer...

  • Can a FlexAir Pin Box be Used with an Andersen Ultimate 5th Wheel Connection
  • Because the FlexAir pin boxes have a part that pivots it should not be used with the Anderson Ultimate 5th wheel connection. You can however use the Trailair equivalent which is # LC158778 for the Lippert 1621 pin boxes.
    view full answer...

  • How to Choose the Correct Trailair Pin Box for Keystone Laredo
  • In order to choose the correct Trailair Pin Box for your Keystone Laredo you will need to know the manufacturer and model number of your current pin box, which should be on a sticker or stamp somewhere on the pin box itself. If you cannot find it, simply call the trailer manufacturer with your VIN and they should be able to tell you what pin box it is. You will be able to select the correct replacement from there. For example, the Trailair # LC155943 is designed to replace Lippert 1116...
    view full answer...


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Info for this part was:

Edited by:
Lindsey S
Expert Research:
Michael H
Expert Research:
Jameson C
Expert Research:
Adam R
Installed by:
Kathleen M
Written by:
Shelly K
Photos by:
Jeffrey L
Updated by:
Hannah L
Updated by:
Kristina F
Updated by:
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