pivoting frames and mounting campers

[rruff]

I have a much lighter rig, but I have 2 of the isolators on each front corner and 2 on the centerline in the back. Think 4 in the back would have been better, but I would have needed a 6" wide beam to fit two in-line and I didn't think that would fit around the spare, using the stock mounting points. These are the low durometer ones from ES. https://www.energysuspensionparts.com/9.4102

How much weight will you be carrying?

EDIT: While I'm handing out potentially silly advice, you should definitely try to find as much as you can about how the beds were actually mounted on these frames. They learned by experience how to do it. I will say that mine articulates well, handles well, and I like having the camper stay more even with the cab rather than pivoting in the rear.

 

[Victorian]

We just got our spring mounted subframe installed on a GMC topkick. The amount of frame flex these trucks have is impressive! Even the drivers cab is 3 point mounted. Can’t imagine the damage a subpar subframe could cause to a habitat.

 

[Cactus101]

No idea, I'm gunna guess around 1500-2000kg. I got an old truck box body rhs framed so I figured that would be pretty sturdy. Going to try and put water tanks in the chassis to lower the gravity and save on camper box weight.


that's an interesting rubber mount design, similar to that spring mounting design as above, why not just go for a pivoting system?

 

[gator70]

These are for sale

 

[mog]

We just got our spring mounted subframe installed on a GMC topkick. The amount of frame flex these trucks have is impressive! Even the drivers cab is 3 point mounted.

@Victorian, that is beyond awesome! And should be a sticky for 'How to build a subframe'.
It is certainly going to be the most capable moving truck in the Western Hemisphere

 

[nnamssorxela]

Hi all, still dreaming up my flat bed, and ready to start building this spring. The only thing I keep flipping back and forth on is what to do for the actual pivots.

Initially I was set on the builder bushings that I believe idasho used, but I do not like the idea of 3 poly bushings carrying the entire load.

Currently I'm thinking of using 1/4" wall 2" OD DOM tube for the inner section mounted to the flatbed subframe, a 1/4" thick bronze bushing, then a 2.5" ID piece of DOM for the outer part mounted to the truck frame.

Are there other/better suggestions?

 

[rruff]

Initially I was set on the builder bushings that I believe idasho used, but I do not like the idea of 3 poly bushings carrying the entire load.

Don't know what your build looks like at all, but... A few posts above I listed Energy Suspension poly bushings. They are cheap... and I was told a static load up to 800 lbs was ok for each. A 1/2 bolt goes through them. Use as many as you want; the subframe would be "fixed" in the front (wide spacing) but you can use several bushings to achieve that, and further back you can space them along the length but in the center only, and they will pivot easily. I doubt you will twist so much that you exceed their range, but that might be something to check.

 

[nnamssorxela]

Don't know what your build looks like at all

It's an '03 4 door long bed f250. C-channel frame, not fully boxed.

I actually have the energy suspension bushings, but decided I want to do a "real" pivot system.

 

[rruff]

I actually have the energy suspension bushings, but decided I want to do a "real" pivot system.

You can do a "real" (enough) pivot system with these if you arrange the rear ones on the centerline. As I recall from reading this thread, if you use fixed metal pivots you'll introduce stresses because the 3 points don't "want" to stay aligned. The poly mounts allow for some movement in all directions, and also allow you to spread out the loads better. Seems better to me, but there are many ways that work...

 

[frabraha]

This is a subframe that I've designed, based on what I've seen professionals have made subframes. The subframe is 6.5 meters long and 2.5 meter wide. I've yet to decide what type of mountings to the chassie, might be rail on rail.

For my subframe I've added rails inbetween the cross frame, to have a pull-out platform.

Since I'm not an engineer my question is, is this pull-out platform possible?

 

[rruff]

The only obvious issue I see is where your platform is interfering with the rails.

 

[gator70]

I'm building spring mounts for my subframe, I searched the world to buy them and there was only one supplier for $500 each. I thought that was crazy.

I made mine out of c-channel 5"

Bolts to truck frame, is welded to sub frame.

They have dual springs each. And I will use three on each side.

 

[frabraha]

The only obvious issue I see is where your platform is interfering with the rails.

Forgot to mention that these parts are removed before taking the platform in.

 

[stever1000]

I'm building spring mounts for my subframe, I searched the world to buy them and there was only one supplier for $500 each. I thought that was crazy.

I made mine out of c-channel 4"

Bolts to truck frame, is welded to sub frame.

They have dual springs each. And I will use three on each side.

Do you have photos of this installed?

 

[stever1000]

There is a huge amount of twist there, just between the cab and bed... extreme.

I made a sort of 3-point using poly cab mounts from Energy Suspension.... just put the rear ones on the centerline so they pivot, and bridge across the frame rails to support them. They pivot easily when arranged that way. I'd suggest putting the "fixed" points spread wide in the front (which are also poly mounts) and the rest in the center. ES told me they were good for 800lb static load each, but I don't have that much weight on them.

Interesting concept - do you have any photos?