Does Curt Helux Pin Box Use Same Bolt Holes as Pin Box it Replaces
Updated 04/06/2026 | Published 03/28/2026
Question:
I have a 2025 Alliance 385 FL. 2970 lb pin weight With curt roto flex pin box. If I replace it with curt Helux pin box with spring and shock. not air. What bolt holes would I use for the 5th wheel to set on truck the same. Thank You
asked by: Kelly C
Expert Reply:
Hey Kelly, the Curt Helux cushioned pin box part # C65MJ will use the same mounting holes that your current pin box uses. These pin boxes are designed to be dimensionally as close as possible to the pin boxes they replace which allows you to use the same bolt holes. How did you like the Roto Flex?
(click to enlarge)
Gregg H.
4/3/2026
I have a Ram 3500 SRW with a B&W Companion Slider hitch. When I changed to the Curt Helux pin box on my 385FL, I had to use the highest level of bolt holes in the frame to maintain the previous ride height of the trailer to bed clearance runs 7-8". You will love the ride. it used to be that on really rough bridge transitions i would bottom my truck suspension out. Since adding the Helux over the same roads and loads I have not bottomed out. it is going to save the trailer and save the truck suspension.
Jameson C.
4/6/2026
Product Page this Question was Asked From
Curt Helux Shock-Absorbing 5th Wheel Pin Box - Lippert Rhino - 24K GTW - 4,000 lbs TW
- 5th Wheel Pin Box
- Upgraded Pin Box
- Absorbs Road Shock and Reduces Chucking
- 24000 lbs
- Rubber Spring Suspension
- Fixed Turret
- Lippert Rhino
- CURT
more information >
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on 5th Wheel Pin Box
Russell G.
3/31/2026
Kelly, Jameson is correct. We replaced our Curt Roto Flex with the Helux and the bolt holes were properly matched. And towing is much more comfortable. If you haven’t purchased the Helux yet, we recommend you proceed.