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Curt Helux 5th Wheel to Gooseneck Shock-Absorbing Pin Box Adapter - 20K GTW - 2,350 lbs TW
(28 reviews)
Price: $1,735.95
In Stock
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Curt Helux 5th Wheel to Gooseneck Shock-Absorbing Pin Box Adapter - 20K GTW - 2,350 lbs TW
Part Number: C22UB
In Stock
$1,735.95
Retail:$2,288.95
You Save: $553.00
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- All Info
- Reviews (28)
- Q & A (0)
- Photos
CURT 5th Wheel Gooseneck Adapter - C22UB
- 5th Wheel Trailer to Gooseneck Hitch
- Replaces Pin Box
- Shock Absorbing
- CURT
- Adapts Trailer
- Lippert Rhino
- 20000 lbs
- No Extra Clearance
Start towing your fifth wheel with a gooseneck ball without losing comfort. A built-in coil spring smooths out bumps and cuts down on chucking. And with the bed cleared, your truck stays useful for gear or daily driving when you're not towing.
Highlights
- Smoother Towing Experience: Coil-spring and shock system cushions bumps and reduces chucking.
- Gooseneck Conversion: Replaces your 5th-wheel pin box with a gooseneck coupler that keeps your truck bed clear when not towing.
- Less to Maintain: Coil-spring design eliminates airbag upkeep and valve issues found in other systems.
- Warranty-Approved Fit: Bolts to the Lippert Rhino pattern with included hardware and is approved for Lippert frames so you don't risk your warranty.
- Tested for Strength and Reliability: Heavy-duty steel construction validated to SAE J2638 standards.
- Quick, Confident Hookup: Auto-latching coupler locks onto a 2-5/16" ball for fast, secure hitching.
Features to know about
Gooseneck Conversion with Built-in Shock Absorption
Switching from a fifth wheel pin box to a gooseneck coupler isn't just about changing the connection. With this setup you get the benefits of a gooseneck (a clear truck bed when you're not towing and a simple ball connection when you are) while also gaining a smoother ride. The coil spring softens the bumps you get with a rigid coupler. Plus, it'll take the edge off when you cross bridge joints and dips that usually set off back-and-forth chucking.
Custom Installation
This pin box bolts directly to the Lippert Rhino pattern with included hardware and it's approved for Lippert frames, so you can install it without worrying about your warranty. It's heavy enough that you and a friend should handle the lift, and following the torque specs is key to getting it set correctly. If an extra set of hands isn't available or you're not comfortable doing this yourself, we can help you find a trusted shop to install it for you.
Quick, Confident Hookup
The auto-latching coupler drops onto your 2-5/16" ball. But, the cool part is that it'll lock in on its own. You just back in, line up, and it clicks into place. That saves time when you're getting ready to head out of the driveway. When you're ready to unhitch, the release is just as simple.
Low Maintenance by Design
One of the frustrations with air-ride systems is checking the pressure or having to top things off. Or even worse, trying to find a leak. The coil spring design avoids all of that. There are no bladders to inflate and no valves to fail. It'll stay ready between trips, so you can just hitch up without adding more things to your checklist.
Specs
Application:
- Gooseneck ball: 2-5/16"
- Compatible with Lippert Rhino pin box bolt pattern
- Approved for use on Lippert RV frames
Weight Capacity:
- Gross towing weight (GTW): 20,000 lbs
- Minimum pin weight: 1,350 lbs
- Maximum pin weight: 2,350 lbs
- Optimal pin weight range: 1,650 lbs to 2,144 lbs
Construction and Color:
- Material: carbon steel with powder coat
- Color: black
Warranty:
- Pin box: limited lifetime warranty
- Finish: 1-year
- Parts: 1-year
Notes:
- Not compatible with Curt Rockerball cushion hitch gooseneck ball.
- Your trailer's pin weight must be between 1,350 lbs and 2,350 lbs for the shock absorption to function as designed.
What is Pin Weight and Why Does it Matter?
Your trailer's pin weight is the amount of weight pressing down on your truck through the king pin. It's the key factor in choosing the right Curt Helux pin box since each model is tuned to a specific pin-weight range. If it's too light, the coil springs won't engage correctly, but if it's too heavy, you'll overstress the system. When this number is accurate, the pin box performs the way it was designed and gives you the smoothest ride possible.
How to Accurately Measure Pin Weight
The most reliable method is to use a set of certified vehicle scales (like CAT scales).
- Step 1: Weigh your truck and trailer together with the trailer hitched (truck front axle on Scale 1, truck rear axle on Scale 2, and trailer axles on Scale 3).
- Step 2: Record the weights from Scales 1 and 2, then add them together. This is Weight A.
- Step 3: Unhitch the trailer and weigh the truck alone (front axle on Scale 1 and rear axle on Scale 2).
- Step 4: Record the weights from Scales 1 and 2, then add them together. This is Weight B.
- Step 5: Subtract Weight A from Weight B. The difference is your actual pin weight.
This process accounts for how your trailer is actually loaded, which includes cargo and water tanks, so you know you're picking a pin box that matches the conditions you're using it with.
How to Estimate Pin Weight
If you don't have access to a scale, you can get a ballpark figure with your trailer's GVWR:
- Step 1: Find the GVWR on the trailer's specification sticker.
- Step 2: Multiply that number by 0.22.
- Step 3: The result is your estimated pin weight.
This method gives you a starting point, but remember it's only an estimate. The actual pin weight can change depending on how you fill tanks and distribute weight in the trailer.
2024044575 Curt Helux 5th Wheel to Gooseneck Shock-Absorbing Pin Box Adapter - 20K GTW - 2,350 lbs TW
Installation Details
Ratings & Reviews
4.7
28 reviews
by:
Ryan Warzynski
09/10/2026
Always impressed with etrailer and the products they stock. We upgraded our pin box from a standard rhino to the Curt Helix. Very impressed in the quality of the product, about twice the weight of the old one. Assembly was super easy, 10 bolts out and 10 bolts in. I would have liked to see a few pre-tapped spots for mounting the wire harness and trailer emergency brake cable. Hatted to use a self tapper to mount it but still easy. Great product, highly recommend-
by:
Jim
09/13/2026
Arrived ahead of expected delivery ( 2 days ) early. Once I get back from vacation I will get it installed on the 5th wheel. Joanne was fantastic to work with at e trailer.
Christopher H.
9/17/2026
Let us know how the install goes Jim! Happy Joanne was able get you taken care of.
by:
Russell
11/24/2025
Purchased over one month ago, I waited until I had towed our 40’ fifth wheel before rating and reviewing the Curt Helux, which replaced the OEM Curt Rota Flex. What a difference! We towed nearly 500 miles and it was the smoothest tow we have had in three years. Very little chucking was encountered even though the interstate had the usual rough bridges and construction. Installation was relatively easy-just follow the instructions-since it was a Curt product being replaced. ETrailer’s service was excellent as well.,
Lazer S.
11/25/2025
Glad to hear you are happy with it, Russell! These Helux pin boxes are still fairly new to market, so are always happy to hear real world feedback, so thanks for that! ^___^ What kind of 5th wheel did you install this on?
by:
Tim
08/16/2026
Arrived well packed, installed easily.
by:
Kurt
10/25/2026
Easy installation, soft, smooth ride. Saves bed space. Great product.
by:
Charles
05/28/2026
Installed this on Our 2024 Brinkley Z3400 witc had a standard pin box from factory. I will say it was one of the best upgrades I have done, much better ride and less noise.
by:
John
11/10/2025
I’ve only had my toy hauler out one since installing the hitch but went over a set of RR tracks and 3 bridges and it definitely makes a difference. Greatly soften the blows to the truck so you know it’s taking a lot of stress off the fifth wheel. Watched it workings through the rear view mirror. Simple design that someone should have come up with long ago. Took a friend of mine and I exactly 1 hour to install withe the help of his motorcycle jack on the tailgate of the truck. It’s heavy and well built. They are a little pricey but I feel well worth it for the longevity of the frame. Most importantly know the weight of your trailer loaded to pick the right one
by:
Michael
05/16/2026
Install was easy, used my tractor to put in position. Only issue it didn’t come with the hardware, had to purchase new. Otherwise good.
by:
Keith
03/13/2026
Great communication and quick to handle any issues
by:
Rick
10/29/2025
This pin box is absolutely amazing. Way smoother pull way less chucking ! Highly recommended this over any stock pin box.
by:
Dale
04/27/2026
Seems very well made. I haven't towed with it yet. I'm very excited to try it.
by:
Tim
05/03/2025
I received this curt helux pin box very quickly. I was impressed with how fast and how the shipment was handled. I've installed the pin box but haven't yet towed our 5th wheel yet. 1st camping trip later this month possibly. Maine weather needs to be a bit nicer. Anyway. So far very impressed with the product.
by:
Mike
08/19/2025
Glad the pin box was good. The box and pallet were damaged badly. Will be installing it tomorrow. I think it will enhance our ride while towing.
by:
Dale
08/28/2025
Easy to install. Works great. There is a noticeable reduction in chunking.
by:
Brett
10/26/2026
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Suzanne
07/21/2026
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Michael
03/21/2026
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Stephen
06/24/2026
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Thomas
07/06/2026
Kate F.
7/13/2026
Thanks for taking the time to leave a review. I'm glad to hear the Helux is taking the harshness out of the bigger bumps, although I'm sorry to hear the chucking has gotten worse. The first is making sure the trailer is towing as level as possible, since a nose-high or nose-low attitude can make chucking much more noticeable. It's also a good idea to verify your trailer's loaded pin weight. If it's significantly lighter or heavier than expected, it can affect how the suspension in the pin box performs. Finally, take a look at your hitch height and make sure everything is torqued to the installation specifications, as any movement in the hitch or mounting hardware can add to the sensation of chucking. What pin box did you replace?
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Marc
05/01/2026
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A
06/21/2026
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Perry
05/07/2026
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Richard
03/09/2026
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William
10/16/2025
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Don
01/15/2026
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See what our Experts say about this CURT 5th Wheel Gooseneck Adapter
- Recommended Curt Helux 5th Wheel to Gooseneck Pin Box It will, so long as your 2022 Cougar 24rds came with the factory Rhino Box Michael. The Curt Helux item # C22UB is designed exclusively for the Rhino Pin Box bracket and bolt pattern. It looks like there were two options for pin boxes on your Keystone Cougar so I can't confirm. However, if I can get some additional information from you I'll be able to. First thing you can do is just look at your pin box. If it says Rhino on it anywhere then you're good the item # C22UB fits. If it doesn't...
view full answer... - Will Curt Helux 5th Wheel To Gooseneck Adapter Be A Good Upgrade For 2026 Alliance Avenue 25RL ?Hey there Ron, Yes, based on your photos the Curt Helux # C22UB would be the correct replacement for the Rota-Flex on your 2026 Alliance Avenue 25RL. Your Rota-Flex uses the Lippert Rhino bolt pattern, which is exactly what the # C22UB is designed to replace. The only thing I’d verify is your actual loaded pin weight. The # C22UB is designed for 1,350 to 2,350 lbs of pin weight, and your Avenue has a listed dry hitch weight of 1,350 lbs, so you should fall within that range once loaded,...
view full answer... - Replacement Shock Absorbing Pin Box For 2022 Grand Design 150 Series Hey Tony, that’s a really good question, and you’re right to double check this before ordering since getting the wrong pin box can turn into a big headache. No, The Curt Helux gooseneck adapter, part # C22UB, will not replace your pin box because it only fits fifth wheels with the Lippert Rhino bolt pattern. Most 2022 Grand Design Reflection 150 Series trailers typically come with a Lippert 1621 pin box instead of the Rhino, and if that’s what you have, this Helux won’t bolt up. Because...
view full answer... - B&W Turnover Hitch For 2026 Silverado And Shock Absorbing Gooseneck Hitch On 2027 Cougar 290rlsHey Stan, Congrats on the new Cougar! Converting to a gooseneck setup sounds perfect for what you're wanting, since you won't have to lift a heavy fifth-wheel hitch in and out of your truck. You are spot on with installing the B&W Turnoverball Underbed Gooseneck Trailer Hitch w/ Custom Installation Kit - 30,000 lbs # BWGNRK1020 into your 2026 Silverado 2500. I'd then recommend one of these shock-absorbing options depending on your factory pin box: If the Lippert Rhino bolt pattern: CURT...
view full answer... - Can I use the BXR 2100 hitch with Curt Helux Pin Box Hi Gary, that’s a really smart question to ask and you’re right to be thinking about how these components work together. The Curt Helux 5th wheel pin box like part # C65MJ is not recommended for use with gooseneck adapters like the Blue Ox BXR2100. The Helux already has a built in coil and shock system to absorb movement, and adding an adapter changes how force is applied to the trailer frame, which can lead to added stress over time. That’s why manufacturers advise keeping that style of...
view full answer... - Gooseneck Pin Box Upgrade For A 2022 Jayco Eagle 321RSTS With Lippert Rhino Pin BoxHi Richard! We definitely have options for converting your 2022 Jayco Eagle 321RSTS to a gooseneck! I will say that we don't have any Reese products though. Their parent company (First Brands) has been having some... "issues" as of late and their parts are basically impossible to get ahold of. Look them up online and you will see what I mean. With that said, check out the following parts: MORryde GooseTech 5th Wheel to Gooseneck Pin Box for 11.5K to 14K Trailers w/ Lippert Rhino # MR74MV Curt...
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Kate F.
9/14/2026
Thanks for the great review, Ryan! Going from the standard Rhino to the Curt Helix sounds like a really nice upgrade. Glad to hear the install was straightforward and you’re impressed with the quality. Thanks for the pictures too! Where did you go for the first big adventure with the new pin box?