Arrives before Christmas 
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Enjoy smooth, stable towing with your fifth-wheel trailer by replacing your ordinary pin box with this air-ride-equipped model. An internal air bag and built-in strut absorb road shock so that you won't feel it. Replaces Lippert 1621 pin boxes.
Features:
Specs:
Note: Do not use the Curt air ride pin box with any type of gooseneck adapter.
Getting there is half the fun, right? Not if you're being bumped, jerked, jammed, and pushed around from the chucking and road shock 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 Curt air ride 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.
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. But the Curt air ride pin box absorbs shock and cushions your ride as you pull your fifth-wheel trailer. When you encounter uneven terrain on your trip or hit a pothole on the highway, the Curt air ride 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, or tow vehicle frame from enduring a rocky ride.
A built-in strut, or shock, controls the Curt air ride pin box'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.
Simple Setup and Installation
First, simply remove your existing Lippert 1621 or 1621HD pin box from your trailer. The Curt uses the same bolts that held on your original pin box so no additional hardware is required for installation. Plus, the Curt pin box comes out of the box ready to be put on your trailer, so no assembly is needed. Because the Curt 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 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.
California residents: click here
The pin box worked out very well. You still feel the bumps but almost no chucking. My wife likes to sleep in the truck with her head against the head rest, but she could not do that with the old pin box. The only thing that I had to do with the new pin box was drill out the holes because the old pin box had bigger bolts.
We have put over 6,000 miles in the last year since we installed the Lippert Air Ride Pin Box hitch. Our trailer is a 42-foot 5th wheel and weighs around 14,000 lbs. The hitch has reduced the jarring and bouncing on both the truck and trailer. Although the hitch is heavy, we had the deliver driver off load it to the back of my truck. Wife and I installed it using the trailer jacks to lower to align the bolt holes and install the bolts. Everything lined up and installed in about two hours. Highly recommend if you pull a heavy bigger trailer.
This is a real nice unit. I uninstalled the Roto-Flex unit first with ease. The new air ride piece slid right into place with ease with the use of a small floor jack and a pin-bar to guide the alignment. The shock was installed backwards with the arrow and line to the rear so I was barely able to see it. I will make a white paint marker line and rotate the shock. I haven’t hauled with it yet; I will update this afterwards.
As long as you have the correct lifting mechanism, it's pretty simple to replace your existing hitch. After install, easy to fill to desired firmness for the ride. As for the ride, definitely less chucking and less rocking of the camping(noted my less things moved around in the camper when we arrive at our destination).
Best ride I ever had.my 42ft.RV rides like floating on a cloud.
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.
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.
Chris G.
11/24/2024
Update after 1 year of use and thousands of miles. Still the best upgrade I could have done. Ride is great, product holding up well. No issues at all. Would purchase again
Swapped out the MorRyde cushioned pin box. This Air Ride is awesome
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!!
All went good
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.
I gave it 4stars because it works really well. The only reason it doesn’t get a 5 is because of powder coating isn’t the best and in a few places it started rusting in less than 6 months. I had to sand areas and use rust resistant paint to keep it from getting worse. Other than that it works fine.
Victoria H.
4/3/2025
That's not the best experience Derek. I'll see what I can do to get a paint credit sent to you.
With the help of my wife, I had the Flex Air pin box installed within 1.5 hours. Used a floor jack on top of my pickup tailgate.
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.
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..
Bernie C.
5/26/2020
I still love the ride it provides- always smooth. Wouldn’t use a standard kingpin again. The airbags lose air over time- it’s my only complaint. Not enough to effect performance on a week-long trip but it loses air. I tightened the fill valve. Will re-tape the valve again if needed.
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 etrailer.com 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.
Charles F.
10/26/2023
Still very pleased with my purchase and reassurance it gives me against future problems.
Added this pin box to improve ride and give my rv a smoother pull. The owners manual says you can use the orginal nuts and bolts, but felt getting new ones that are grade 8 was the best route for me.
The pin box had several deep scratches due to shipping so I mounted it and then painted over the scratches and resolved the problem.
The rebound shock didn't have the yellow arrow like the one in the pictures, does have an max inflation stamped in the shock but black on black doesn't help for proper inflation so I painted the arrow yellow, not great but it works.
Number one issue is no matter the inflation of the airbag I can't get it too the top of the arrow as required. I checked the PSI on the airbag and was at 135 PSI. I felt that was too high of air pressure and there's nothing in the manual or online to say how much air should be in an airbag so I went with 98 PSI to be safe.
As for the ride I feel it was an improvement over the previous pin box but to be honest my F450 has airbags as well, so was the improvement due to the pin box or because of the truck airbags. I'll go with both had factors with the ride. But the number 1 factor for me was the 21000 weight capacity. 4 out of 5 is the issue with inflation and what's correct.
David M.
3/4/2022
Its been a year since last review, still havent had any issues with the pin box. Works well and provides a smooth ride under most conditions. If you run into rough patches on the road youll feel it and in my opinion there isnt anything made today that will eliminate that type of chucking. I also have airbags on my truck and it still happens. Now for the pin box 1. It works as advertised and improves the ride substantially. 2. The pin box is very well built and no issues period. 3. One issue is the air valve on top of the pin box which makes you get up into the truck bed to fill it with air. What would be a improvement would have a extension that attaches to the valve that would allow you to add air without having to get into the truck bed. To summarize, this pin box has been a great investment and if youre looking a replacement box, youll be happy you purchased this one.
The trailair pin box I ordered and received looks be be everything I was told it would be. I have not bin able to road test the hitch yet as it's only early March and living in north east Minnesota, we still have about two feet of snow . I'm sure hoping it works as well as its supposed to.
Dean S.
3/7/2021
I lovin the ride with this air ride pinbox. It works well for the ride on both truck and trailer, glad I decided to make the investment.
I still haven't received this item
Gwendolyn Y.
12/10/2024
Hey John. I checked on your package and it shows that it was delivered on 12/9 around 10am. I wanted to make sure that you did get your delivery. Let me know!
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.
Have the Lippert Components Trailair fifth wheel king pin installed on our 40 foot Big Country has made the difference in pulling the trailer down the road. I would recommend the King Pin if pulling a fifth wheel trailer. Now we don't even know it behind us. Great Product.
This is the 2nd air ride hitch i've purchased. First one was on another 5th wheel and stupidly didn't keep it when I traded for the one I have now. They work great! It takes the shock out of the bumpy roads and keeps camper insides from re-arranging when traveling. Very happy with the hitch.
Took all the transfer of trailer hunting out of tow vehicle as you travel. Also give me more turning clearance on short bed F250.
Dale H.
10/5/2021
Makes hook up a snap!
Really made a positive improvement in towing my RV. The hitch absorbs the shocks from the trailer when towing and therefore the ride is much better in the tow vehicle. I also think it works the other way as well, RV is somewhat shielded from shocks the tow vehicle is experiencing. Am so impressed that I moved it over to our new RV. Well worth the time and cost to buy and install.
Smooths out the porpoising when traveling over rough roads and at uneven bridge abuttments.
Weldon
6/18/2024
Still great. Previously on long bridges at the coast I would need to slow down to 40-45mph crossing due to excessive porpoising due to the eneven bridge sections. This air bag hitch pin setup eliminated that and I can cruise along with traffic at normal highway speeds.
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Jimmy
5/12/2024
still works great.