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  1. 5th Wheel Pin Box
  2. CURT
  3. Lippert Rhino
  4. 18000 lbs
  5. Upgraded Pin Box
  6. Absorbs Road Shock and Reduces Chucking
Curt Helux Shock-Absorbing 5th Wheel Pin Box - Lippert Rhino - 18K GTW - 2,600 lbs TW
CURT

Curt Helux Shock-Absorbing 5th Wheel Pin Box - Lippert Rhino - 18K GTW - 2,600 lbs TW

Part Number: C25MJ
In Stock
$1,495.95
Retail:$1,971.95
You Save: $476.00
5th Wheel Pin Box
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Tired of your trailer tossing you around? Curt's Helux pin box smooths things out with a tough coil spring that beats air bags and torsion setups. It's maintenance-free, easy to use, and won't put your RV's frame warranty at risk. 1-800-940-8924 to order CURT 5th wheel pin box part number C25MJ or order online at etrailer.com. Free expert support on all CURT products. Great prices and Fastest Shipping for Curt Helux Shock-Absorbing 5th Wheel Pin Box - Lippert Rhino - 18K GTW - 2,600 lbs TW. 5th Wheel Pin Box reviews from real customers.
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CURT 5th Wheel Pin Box - C25MJ

  • Lippert Rhino
  • 18000 lbs
  • Upgraded Pin Box
  • Absorbs Road Shock and Reduces Chucking
  • CURT
  • Air Ride Suspension
  • Fixed Turret

Tired of your trailer tossing you around? Curt's Helux pin box smooths things out with a tough coil spring that beats air bags and torsion setups. It's maintenance-free, easy to use, and won't put your RV's frame warranty at risk.


Highlights

  • Smooth, Cushioned Ride: Internal spring helps absorb road shock and reduce aggressive bouncing and chucking.
  • Ultimate Comfort and Protection: Eases fatigue, minimizes wear on your RV and cargo, and helps your trailer ride smoother every time.
  • Zero Maintenance: No airbags, bearings, or bushings to service, just hitch up and go.
  • Built to Last: Fully welded steel with a triple-layer powder coat stands up to rust and wear.
  • Trusted in the Industry: Approved for Lippert RV frames, so it won't void your trailer's warranty like some aftermarket pin boxes.

Made in USA

Features to know about

Smoother Ride, Better Protection

Helux in use

The Helux coil spring system absorbs road shock, jerking, and the back-and-forth chucking that wears you out on long drives. It keeps things steady through starts, stops, and uneven roads so your ride feels calmer, your cargo stays safer, and your trailer takes less of a beating.

Durable and Maintenance-Free

Built from fully welded steel with a triple-layer powder coat, this pin box is made to handle years of towing and all kinds of weather. And with no airbags, bearings, or bushings to service, you won't have to think about upkeep.

Lippert Approved Upgrade

Unlike some aftermarket pin boxes, this one is approved for use on Lippert RV frames. That means you get a smoother ride without risking your trailer's warranty.

Specs

Application:

  • Compatible with Lippert Rhino pin box bolt pattern
  • Approved for use on Lippert RV frames

Weight Capacity:

  • Gross towing weight (GTW): 18,000 lbs
  • Minimum pin weight: 1,200 lbs
  • Maximum pin weight: 2,600 lbs
  • Optimal pin weight range: 1,880 lbs to 2,377 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 offset 5th wheel hitches.
  • Your trailer's pin weight must be between 1,200 lbs and 2,600 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).


pin box measurements

  • 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.



2024044568 Curt Helux Pin Box - Coil Spring Shock Absorption - 2,600 lbs Pin Weight

Installation Details C25MJ Installation instructions


California residents: click here


Ratings & Reviews

4.9

10 reviews
Tired of your trailer tossing you around? Curt's Helux pin box smooths things out with a tough coil spring that beats air bags and torsion setups. It's maintenance-free, easy to use, and won't put your RV's frame warranty at risk.

by:



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Easy to install. Works great. There is a noticeable reduction in chunking.



by:

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:

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:

This pin box is absolutely amazing. Way smoother pull way less chucking ! Highly recommended this over any stock pin box.



by:

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:

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.,



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See what our Experts say about this CURT 5th Wheel Pin Box


Info for this part was:

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Updated by:
Lindsey S
Employee Wilson B
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Employee Alex H
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Alex H
Employee Jameson C
Expert Research:
Jameson C
Employee Katherine B
Edited by:
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