Total Composites flatbed build

[andy_b]

LOL yes. The thing is: If we create drawings/ instructions on how to do subframes, it will only be a matter of time till others take our info to their advantage and undercut us. There is a reason why there is no info to be found online. Then there is also the liability issue...
Trust me if there would be an easy answer/solution, we would be the first in offering it!

If the solutions are so unique, then arguably, they are IP that you can protect and maybe worth the hassle from a business perspective. On the other hand, if I'm right and it is just math that needs to be worked out to get repeatable and reliable results, then it would be nice if that were available to those of use who are interested.

Anyhow, an argument can be made that this same thing is could happen when you share examples of your panel construction. The value Total Composites adds is beyond the product, amirite? Otherwise, I could just get Lamilux FRP, foam, adhesive, and really really DIY. But, I don't want to and I appreciate the value that Total Composites provides. Just sayin'.

 

[rruff]

Protecting IP is something that big companies can do, but not small ones. And the only IP worth protecting is on higher volume designs ($$$).

Every truck+camper is in fact unique in many ways. There is plenty of info on the internet showing various dynamic subframe designs and you can just copy one if you wish. I know Idasho used a 3 point mount with a rear pivot on his Ford, and he must have liked it because he did the same thing when he built a new flatbed. That or the 4-point that Victorian linked is pretty simple and seems to work.

 

[GoinBoardin]

Why diamond with 4-point as opposed to the four corners of the rectangle?

Because a rectangle doesn't accommodate frame twist without translating that twist straight into the camper. Diamond shape does. Another advantage over a three point is you end up with four contact points with the frame vs three.

Curious what your setup is like. Do you have a description somewhere?

On my truck the frame is only flexy in the rear, which is where the "pivot" will be. Not really a pivot, but 4 poly cab mounts spaced close to the center. As you noticed, if you hard mount the rear, the camper will follow the tilt at the rear of the frame. If you hard mount the front, the camper will stay even with the cab (or close anyway).

I have a build thread for the camper in the popup section, with the pivot mount stuff near the end. It's nothing fancy but gets the job done. About 6200# all in for a quick trip so I didn't have to over engineer things the way heavy trucks would require. I've since upgraded the truck suspension substantially. Here's a link (post 85 &86 are relevant): https://expeditionportal.com/forum/...leet-flatbed-conversion-project.171811/page-6 Initially I had dropped my camper on my flatbed directly, which was hard mounted to the truck frame. After some time I found the front hard mounts were cracking. That's when I built a pivoting sub frame (also saved ~350# over the full flatbed).

About 6 minutes in he mentions what he'd do different; says he'd fix the front and allow pivoting at the rear, rather than the opposite. Early he says that you are kinda chasing your tail, trying to get a decent ride and minimize sway at the same time... tradeoffs that work against each other.

I find it interesting this guy reached the same conclusion I did. My rig is a couple times lighter but still the same principles apply.

 

[IdaSHO]

Every truck+camper is in fact unique in many ways. There is plenty of info on the internet showing various dynamic subframe designs and you can just copy one if you wish. I know Idasho used a 3 point mount with a rear pivot on his Ford, and he must have liked it because he did the same thing when he built a new flatbed. That or the 4-point that Victorian linked is pretty simple and seems to work.

Many reasons I went with a 3 point, and not a 4-point or spring mount.

A 3-point is stupid simple, ultimately only requiring proper strength and fabrication of the subframe.

A 4-point creates a situation where one of the tips of the diamond may become out of plane with the others.
This creates binding. Not really a problem in theory, but real life proves that every chassis presents different hurdles to accomplish this.
Some applications it simply isnt possible, or remotely cost effective.

A spring mount is a completely different animal. But my biggest issue with it is that when working correctly and springs dialed in,
you are completely reliant upon the strength/stiffness of the subframe/bed/box. So when in use, the box many very well be put under stress.
Stress that the box NEVER sees with a 3 or 4 point pivot. With a 3 or 4 point pivot, the box floats above the vehicle chassis, remaining flat regardless of chassis flex.

 

[IdaSHO]

Also, with regards to TotalComposites, subframes, and drawings...
Liability alone is enough to keep such drawings under wraps, IMO.

There is very good reason why essentially no plans are available for such subframes.
Every application is different, and for "light trucks" the method is very, very new, within a small market.

Does my method work? Yep.
Do I trust is 100%? Not yet....

Its such uncharted territory that everything is uncertain.
What works rolling out of the shop might last 10 miles, or 100,000 miles without failure.

On the current setup, so far we have about 20,000

But as far as providing specifics for subframes, no way.
Best bet is to research what you can, understand the fundamentals of each type of torsion free setup,
get a handle on design/strength requirements, and make it happen.

I do understand that most have trouble with the last two.... design and fabrication.
That's proof positive in a so many of the sketchy builds.

So proceed with caution.

Personally, without having the engineering background, I overbuild, but with my eye on weights, constantly.
It has proven effective.

 

[rruff]

Glad you are chiming in Kenny...

Are you happy with your mount from a performance standpoint... ie sway on the road or trail? I realize that everyone would like a little better performance, and there is always the "compared to what?" question, and suspension is certainly a factor. I'm thinking of the complaints when the rear of the subframe is fixed and the front pivots, and what your thoughts are on that?

 

[andy_b]

Also, with regards to TotalComposites, subframes, and drawings...
Liability alone is enough to keep such drawings under wraps, IMO...

To be clear, I wasn't asking Total Composites to share drawings for free. I'm buying a kit and would buy a subframe and/or pay for engineering if available. My suggestion was to use modern technology (CAD files and laser scanning, for example) to facilitate remote engineering solutions.

 

[IdaSHO]

Glad you are chiming in Kenny...

Are you happy with your mount from a performance standpoint... ie sway on the road or trail? I realize that everyone would like a little better performance, and there is always the "compared to what?" question, and suspension is certainly a factor. I'm thinking of the complaints when the rear of the subframe is fixed and the front pivots, and what your thoughts are on that?

I am happy. It does exactly what it was designed to do.... save the camper from the twisting forces of a flexy chassis.

There are downsides though, as always.

Sway is one of them, but isnt that bad.
Not as bad as is that-terrible-uncomfortable-feeling-in-your-gut.... when severely off camber.
My gut tells me that the weight of the camper goes 100% in the wrong direction in these situations, which exacerbates the already higher COG.
By how much... its hard to say. My brain tells me its a 8,000lb truck with a low COG, carrying a 3,000lb worth of camper and gear.
My gut tells me that COG is much higher than it most likely is.

 

[IdaSHO]

To be clear, I wasn't asking Total Composites to share drawings for free. I'm buying a kit and would buy a subframe and/or pay for engineering if available. My suggestion was to use modern technology (CAD files and laser scanning, for example) to facilitate remote engineering solutions.

I understand, and thanks the the additional clarification.

But to the point, every application is quite literally different.

So my suggest still stands... Research what you can, understand the fundamentals of each type of torsion free setup,
get a handle on design/strength requirements, and make it happen. (and/or find somebody to help)

And expecting to obtain/purchase such plans, that would most likely be altered anyhow, is a stretch IMO.

 

[Deleted member 215671]

Considering the 4 spring points appear to be the only "solid" mounts holding the camper/subframe to the truck could you had safety straps of some kind that could be tensioned down when twisting isn't an issue over say long nicer stretches of highways? Then just loosen them up when you get off the pavement? For example the cargo strap rollers on the sides of flatbed trailers for big rigs. Usually 10k+ rated, very easy to tighten or loosen and parts are available nearly everywhere and at larger truck stop gas stations etc.

I'm not an engineer by any means but seems fairly simple to weld/attach 4 mount points on the bottom of the camper and weld four tiedown winches like this just as an example: https://www.uscargocontrol.com/Storable-Weld-On-Truck-Tie-Down-Winch may add a bit of safety and redundancy?

Now you have the four spring mounts and 4 straps or even chains but they don't wind us as easy/take more room etc. Or even had 4 arms to the frame and use the traditional hold down springs used on truck bed campers. Again just spit balling but I like what you are trying to accomplish and only offering thoughts etc.

 

[IdaSHO]

A bit hard to see, but if you look to the rear of my setup I have integrated shocks that dampen the movement of the bed relative to the chassis.
I chose to use the same shocks the truck uses on the front axle.... You could easily add provisions for straps to limit the movement.
In my experience, these are more useful for when the camper is not loaded, and bed is empty, as the camper adds a considerable amount of rigidity to the bed.
The "superduty bounce/hop" + a flexible bed = a decent amount of movement. The shocks eliminated it 100%

Also, going 3-point or 4-point over a spring mount you can shave weight over a spring mount, as your subframe/bed doesn't have to be nearly as rigid/strong.
Using open C channel, and essentially sheet metal for my bed, the setup is strong, but not terribly rigid.
Considerably stronger than the stock bed, but it flexes as I used zero box tubing.

Another note.....

During high wind/nasty weather camping, I do ratchet strap the rear corners of the bed to the wheels, sucking the suspension down a bit, to stabilize the camper.

 

[andy_b]

Considering the 4 spring points appear to be the only "solid" mounts holding the camper/subframe to the truck could you had safety straps of some kind that could be tensioned down when twisting isn't an issue over say long nicer stretches of highways? Then just loosen them up when you get off the pavement? For example the cargo strap rollers on the sides of flatbed trailers for big rigs. Usually 10k+ rated, very easy to tighten or loosen and parts are available nearly everywhere and at larger truck stop gas stations etc.

I'm not an engineer by any means but seems fairly simple to weld/attach 4 mount points on the bottom of the camper and weld four tiedown winches like this just as an example: https://www.uscargocontrol.com/Storable-Weld-On-Truck-Tie-Down-Winch may add a bit of safety and redundancy?

Now you have the four spring mounts and 4 straps or even chains but they don't wind us as easy/take more room etc. Or even had 4 arms to the frame and use the traditional hold down springs used on truck bed campers. Again just spit balling but I like what you are trying to accomplish and only offering thoughts etc.

The spring mounts allow me to tighten them down as needed for a similar effect. Also allows me to avoid extra stuff attached to my setup. I like the thought, though.

 

[andy_b]

It's time to finalize dimensions and I'd love to get some input from other camper owners.

The length and width of the main body of the camper are dictated by the flatbed, so they are what they are. The alcove is also designed to hold a queen size bed oriented N-S, so that is fixed, too. The only other dimension in height, specifically interior height. I want the camper to be a low as practical. We're short, (5'6" and 5'4"), so this may be the one time we can use that to our advantage, lol.

How close can the ceiling get to your head before it feels claustrophobic or unpleasant? I've had work trucks where the interior height is just above my head so that I could stand up, but not much more. That wasn't great so a little more space would be nice.

I was thinking an interior height of 76" would let it feel pretty roomy without being as tall as many other commerical hardside campers. It would make the exterior height just around 82". Does anyone think I should go lower? 72' - 74"? While resale isn't the main consideration, it does seem reasonable to make the box a height that normal people could also fit it.

 

[ITTOG]

I used a cargo trailer that was 3" higher than my head. It was fine but I do remember thinking if I built one it would be at least 6" above my head. So 74" to 76" sounds more than enough to me for your height.

Sent from my Pixel 3a XL using Tapatalk

 

[1000arms]

It's time to finalize dimensions and I'd love to get some input from other camper owners.

The length and width of the main body of the camper are dictated by the flatbed, so they are what they are. The alcove is also designed to hold a queen size bed oriented N-S, so that is fixed, too. The only other dimension in height, specifically interior height. I want the camper to be a low as practical. We're short, (5'6" and 5'4"), so this may be the one time we can use that to our advantage, lol.

How close can the ceiling get to your head before it feels claustrophobic or unpleasant? I've had work trucks where the interior height is just above my head so that I could stand up, but not much more. That wasn't great so a little more space would be nice.

I was thinking an interior height of 76" would let it feel pretty roomy without being as tall as many other commerical hardside campers. It would make the exterior height just around 82". Does anyone think I should go lower? 72' - 74"? While resale isn't the main consideration, it does seem reasonable to make the box a height that normal people could also fit it.

Will the roof of the alcove be the same height as the roof of the camper's main body, or will they be at different heights? (See @IdaSHO 's camper photo in the quote below.) If the alcove and main body will have the same roof height, that may result in an camper's main body interior height greater than you are currently thinking. Keep in mind that having enough height in the sleeping alcove can be quite useful.

Being able to wear boots and a hat inside without scraping the ceiling might be useful to you.

You don't have to match the camper's main body to the flatbed, but I suggest you have good reasons for exceeding the flatbed dimensions, and keep in mind that you might want a good bumper protecting the rear of your camper.

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