Installing 5th wheel on custom flatbed

[Jason]

I have a standard rail type 5th wheel hitch for my f250. I have removed the rusted out and falling apart bed, replacing it with a flatbed I built. The rails are designed to be bolted to the frame brackets through the floor of the bed. I'm sure the bed would have been capable of supporting some weight on the rails. I bolted treated 4x4 lumber on spacers to each side of the frame and screwed 2x8s perpendicular to the frame. My intent was to be able to remove 2 or 3 of the 2x8s when I need to install the hitch, and have a full flatbed the rest of the time (living in trailer, moving 2-3 times per year). Without the bed there, the rails only sit on the frame. Do they need the support the stock bed would/could have provided, or can I just bolt the rails directly to the brackets?

Thanks,
Jason

[wingnut60]

Don't have an answer for you, but to say the stock bed is a better mount than the frame/rails of the truck, doesn't make sense to me. I have only used B&W hitches, so never used rails.
But, welcome to the forum.

[Primo Rudy's Roadhouse]

In my opinion, the rails should be bolted to the frame of the truck. That is how my rails are attached to my f250. I would not trust the wood to support the stress of the fifth wheel brackets and hitch. I say this not being able to see your fabricated bed.

[friz]

A picture is worth a thousand words. I am interested. Would you post one?

[Druidcat1115]

I agree with Rudy, the rails have to bolt to the frame brackets but you can bolt through the bed as if you were bolting through the original metal bed. DO NOT bolt the rails to the bed alone it will not hold.

[Notanlines]

It is an absolute must that the hitch/rails be mounted to the actual frame of the vehicle. No wood can be involved in the least.