Hitch ball through crossmember?... Maybe..

[Aussie Iron]

What gets me now and a lot of others I would recon is that you have asked about your idea and we have given you our answer which you don't seem to like and are now arguing that your idea is feasible. If you think so then do it. You don't have to try and convince us it's your setup.

Me, I'm saying you are trying to reinvent the wheel, But hey it's going to be your setup.

Dan.

 

[sixbennetts]

Pictures would be great, thanks. That's the nature of discussion, and I'm making changes as I get everyone's input, which is appreciated.

Also watching a lot of videos on YouTube of these trucks/boxes in the outback. They really do flip around a lot!

 

[John M.]

Six, I don't agree with the equivalence comparison of a spring mount subframe to your "full suspension" concept. It just doesn't have the range of motion to create a slinky.

I would suggest that spring mounts are much different because they permit a very limited amount of travel before become a fixed -bolted- connection. I believe we are talking about 30 to 50 mm typically. While one side rises the other remains pressed hard against the truck frame. The truck will flex, raising one rail at time and there's no "boing" in the spring action. Also, I think spring mount subframes are always (almost always?) rigidly fixed to the truck frame at one end, causing the subframe to flex open like a scissor with a vertex controlling the range of motion.

I really enjoy these discussions. This forum has been fantastic for helping me to work through my ideas, and let me take the short path building on other people's trial and error!

Cheers!

 

[SkiFreak]

Also, I think spring mount subframes are always (almost always?) rigidly fixed to the truck frame at one end

That is an option, but I do not believe it is the norm.
The majority of spring mount systems, including my own, have no fixed mounts.

 

[Aussie Iron]

Unless you are going to first build a frame that sits on the chassis to spread the load you are going to put point loading on parts of the chassis and this is what is not recommended. What you are suggesting is what has caused chassis to crack (point loading on parts of the chassis).

I like to be proved wrong,
Dan.

 

[sixbennetts]

Isn't that what a 3-point subframe is? Like the Aussie water tanker trucks, and GXV mogs?

Now I'm really confused...


*edit

Ding-ding-ding! Now I get it, AussieIron! 3 points is ok, as long as the points spread the weight over a larger area! Ok, I see your point!

"I see", said the blind man, as he pissed into the wind.
"It all comes back to me, now".

 

[sixbennetts]

Added 3 blue angle-plates fore and aft to spread the weight of the 2500lbs camper over a larger area. Obviously, these will be bolted on if I can find enough stock holes in the frame, not welded. If there's not enough holes, I'll explore U-bolts. All padded with urethane sheet or sections of conveyor belt.

*excuse the weird angles of the leaf springs and U-bolts. They're only there to help visualize it. And I still have the option to mount the springs either above or below the axle to get it level.

 

[John M.]

That is an option, but I do not believe it is the norm.
The majority of spring mount systems, including my own, have no fixed mounts.

I accept your statement.

I have seen spring mounts with a pair of nested channels that function as telescoping mount. These would control fore and aft shifting and also serve to ensure the rails come back down where they belong.

I have also seen spring mounts that are simply two pieces of opposed angle iron with a sprung bolt (bolts) between them that do nothing to keep the subframe from sliding back and forth.

Should I conclude that it follows that subframes without a fixed end must have the telescoping type? I could also be missing something obvious here....

J.

 

[SkiFreak]

This is a typical spring mount that gives fore, aft and lateral support. It also maintains the position of the subframe, relative to the chassis.
I saw this spring mount system on a Rural Fire Service (RFS) truck that I came across.
There are many other similar setups, based around the same concept.

 

[IdaSHO]

At first I really like the idea of using leafs.

But my gut tells me in doing so, the camper will be turned into a "live-load"

I hope Im wrong.

 

[Lachstock]

Wouldn't having springs on top of springs case a 'double bounce' kind of scenario that aplifies the inital bump into a secondary bump AFTER it should have done the work? There'd be so much dynamis with this setup I'd have thought that the load would be wallowing all over the place slightly out of phase with the trucks suspension...

Makes me nervous!

 

[sixbennetts]

Exactly. By using shocks and limiting straps, I'm hoping to mitigate the possible 'live load' scenario, and mimic the amount of load 'travel' offered by the standard 3-point hitch springs. For a LOT less work, weight, and most importantly to me personally...money.

Looked at a camper yesterday that had torsion axles. That throws a whole NEW twist into the plan! Upside of torsion suspension is a lot less potential spring travel distance, as opposed to a leaf spring suspension.

Hmmm....moose antlers for the axle stubs to ride in.....

 

[sixbennetts]

Torsion might be the best way to go?

-less up/down travel
-zero possibly of spring sideways flex
-more adaptable

...but also...

-more expensive.