Which Sidewinder Will Replace Pin Box With Lippert Rhino Mounting Bolt Pattern

Updated 01/07/2026 | Published 09/13/2024

Question:

Looking to replace the rota flex with my sidewinder from my old trailer, is this pin box compatible with my old sidewinder?

asked by: Doug M

Rota-Flex Pin Box
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Pin Box Serial
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Expert Reply:

Hi Doug,

Appreciate the info, and I reached out to Lippert, who said the serial number you gave for the pin box is a Lippert Rhino pin box bolt pattern. While I'm not sure what specific Sidewinder you have, the correct Sidewinder for a Lippert Rhino pin box is the following:

- Reese Sidewinder 5th Wheel King Pin # RP34FR

So if this is what you have it'll be compatible and allow you to replace your Rota-Flex.

expert reply by: Kyle S

Jerred H.

1/5/2026

Hey Doug, did the Reese Sidewinder end up fitting your Lippert Rhino pin box the way you needed? Knowing how that swap from the Rota-Flex went could help others planning a similar replacement.