Total Composites flatbed build

[andy_b]

Noted on Alum-line. My hope is they will build what I want and ship it to me for mounting. I'll check out Highway Products for sure. I keep holding out hope to find a good used unit here in Utah. I already have an Aussie style "ute" shell made by that I would keep on the flatbed when not in camper mode. Those ARE shells are sort of fragile and my hope is the flex mount will keep it together. I really think flatbeds should all be mounted this way and I'm shocked it's been this hard to find somebody who can do it.

Fingers crossed for Alum-line. They seem to make a great product. I had called in April so maybe they just had corona-brain...

I saw my first Euro-style camper almost 15 years ago and it seemed like such good formula: composite construction, flat floor, dynamic mounting. I figured that by the time I was going to get into one, the US marketplace would have it figured out. ?‍♂️ At least Andreas and Total Composites got the first two covered lol.

 

[Alloy]

I think you're being a little brutal here.

Yes, I agree....for a reason.

 

[rruff]

This dude is an ME and even he thought he didn't quite get it right the first time he built his:

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.

You can test if your springs are too stiff by finding a nice ditch where you can get diagonal opposing wheels in the rut. This will induce a lot of frame twist and you can see how much the flatbed twists.

 

[Alloy]

What your solution is to this problem?

If there was an easy solution I would have mentioned it.

 

[andy_b]

If there was an easy solution I would have mentioned it.

I didn't say it had to be easy. If you're unable to articulate a reasonable alternative, maybe your understanding of the problem isn't as complete as you imagine.

 

[DirtWhiskey]

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.

You can test if your springs are too stiff by finding a nice ditch where you can get diagonal opposing wheels in the rut. This will induce a lot of frame twist and you can see how much the flatbed twists.

Right and I think he has a very compelling case for a solid front mounting rather than solid rear. The "middle" should in theory be the most stable part of the ladder during flex. Sway is induced by weight shifting around, especially off road, so kill two birds, etc.. That was always my question about the solid rear mount. I wonder what the effect of captive springs all around instead of any solid mount at all would be?

 

[DirtWhiskey]

If there was an easy solution I would have mentioned it.

Genuinely curious: WHAT IS YOUR SOLUTION?

 

[andy_b]

Right and I think he has a very compelling case for a solid front mounting rather than solid rear. The "middle" should in theory be the most stable part of the ladder during flex. Sway is induced by weight shifting around, especially off road, so kill two birds, etc.. That was always my question about the solid rear mount. I wonder what the effect of captive springs all around instead of any solid mount at all would be?

Obviously, I wondered the same thing. Part of the reason I liked these mounts is that I could replace the spring altogether and put an isolator of some kind in there instead. I also thought that maybe I could tighten the bolts and essentially increase the preload and constrain movement that way.

 

[DGOlc100]

Definitely following as we want to do something really similar. You also appear to be in my neck of the woods, so if you need help with the TC build when the panels arrive let me know. Would love to see it hands-on. I heard good things about flatbeds from Largo Tank and Equipment in Farmington as well. I think they carry Western Pride flatbeds and also do some custom work in steel and AL too. Did you check with them at any point? Anyhow, DM me if you need a hand. I'm in Hermosa.

 

[andy_b]

Definitely following as we want to do something really similar. You also appear to be in my neck of the woods, so if you need help with the TC build when the panels arrive let me know. Would love to see it hands-on. I heard good things about flatbeds from Largo Tank and Equipment in Farmington as well. I think they carry Western Pride flatbeds and also do some custom work in steel and AL too. Did you check with them at any point? Anyhow, DM me if you need a hand. I'm in Hermosa.

Thanks for the tips. Since I already have a flatbed, I don't really need to source another. As for the help, I appreciate it, but I'm going to be building it waaay out in the Pacific Northwest, because that seemed rational lol.

 

[Victorian]

Here is another very good video about subframes:

 

[andy_b]

Here is another very good video about subframes:

Thanks for the video. Those Unicats are amazing vehicles.

Unfortunately, it doesn't go much into the theory of the design apart from the "we use a pivot." I think the big questions most of us have on ExPo whenever these types of things are discussed are what type of system and why. For example: pivot in front vs back, three point vs four, diamond vs rectangle, damped or not, springs or not, location of pivots, methods and indications for limiting fore/aft and side-to-side movement.

I wish there was a formula to follow such as sizing solar panel wiring or building a 4-link, when in fact it seems much more like a trial and error process. That's why I appreciate the opinions of others but am even more interested in facts or similar builds.

 

[Victorian]

Thanks for the video. Those Unicats are amazing vehicles.

Unfortunately, it doesn't go much into the theory of the design apart from the "we use a pivot." I think the big questions most of us have on ExPo whenever these types of things are discussed are what type of system and why. For example: pivot in front vs back, three point vs four, diamond vs rectangle, damped or not, springs or not, location of pivots, methods and indications for limiting fore/aft and side-to-side movement.

I wish there was a formula to follow such as sizing solar panel wiring or building a 4-link, when in fact it seems much more like a trial and error process. That's why I appreciate the opinions of others but am even more interested in facts or similar builds.

The problem is: every vehicle is different. Especially big trucks. Most of them are ordered custom with attachment points and accessories located all over the place. That alone will prevent anyone from designing a one size fits all solution. Most subframe manufacturers/ box builders require to have the truck on site for taking measurements. I have great contacts in Germany that could design you the most amazing subframes... But they need the truck to do so. We could make a killing just selling subframe drawings and components!
Some manufacturers have very strict parameters on how to mount a box. For example, the fuso (I believe same goes for the NPR) requires to have the subframe fully resting on the frame rails. Therefore only spring mounts are an option as a 4 point would create point loads. I have seen 4 points on the LMTV/FMTV. Also seen spring mounts on the same trucks... Both worked just fine. It's a totally different story with smaller trucks. Even within the same model range (like the F350) you can buy the truck with straight frame rails or with a pick up box and bend frame rails. You see there is no straight answer what's best... But I would always recommend following the truck manufacturers recommendations or consult with a structural engineer. Anything else is just hoping for the best and potentially risking your truck and possible injuries.

 

[andy_b]

The problem is: every vehicle is different. Especially big trucks. Most of them are ordered custom with attachment points and accessories located all over the place. That alone will prevent anyone from designing a one size fits all solution. Most subframe manufacturers/ box builders require to have the truck on site for taking measurements. I have great contacts in Germany that could design you the most amazing subframes... But they need the truck to do so. We could make a killing just selling subframe drawings and components!
Some manufacturers have very strict parameters on how to mount a box. For example, the fuso (I believe same goes for the NPR) requires to have the subframe fully resting on the frame rails. Therefore only spring mounts are an option as a 4 point would create point loads. I have seen 4 points on the LMTV/FMTV. Also seen spring mounts on the same trucks... Both worked just fine. It's a totally different story with smaller trucks. Even within the same model range (like the F350) you can buy the truck with straight frame rails or with a pick up box and bend frame rails. You see there is no straight answer what's best... But I would always recommend following the truck manufacturers recommendations or consult with a structural engineer. Anything else is just hoping for the best and potentially risking your truck and possible injuries.

I don't disgree, per se, but just like designing an anti-squat suspension for a car, while the applications can vary, the physics are still the same. Different wheelbases, tire size, weight distribution - input into formula, and you get linkage locations and control arm lengths. Then you have leverage ratios and can get a starting point for spring rates and damping curves.

I looked at the Ford body builder's guide for this model truck and found very little about how to (or how not to) mount a body to the frame. They did have discussions about weight, how to secure (eg - bolts vs welds), etc, but nothing to do with point loading or chassis flex.

With Total Composite's interest in supplying DIY camper kits, your access to engineering resources, and the availability of CAD drawings and BBGs from the major pickup manufacturers, perhaps it is time to start making that killing? I know I would have taken advantage of that service.

 

[Victorian]

I don't disgree, per se, but just like designing an anti-squat suspension for a car, while the applications can vary, the physics are still the same. Different wheelbases, tire size, weight distribution - input into formula, and you get linkage locations and control arm lengths. Then you have leverage ratios and can get a starting point for spring rates and damping curves.

I looked at the Ford body builder's guide for this model truck and found very little about how to (or how not to) mount a body to the frame. They did have discussions about weight, how to secure (eg - bolts vs welds), etc, but nothing to do with point loading or chassis flex.

With Total Composite's interest in supplying DIY camper kits, your access to engineering resources, and the availability of CAD drawings and BBGs from the major pickup manufacturers, perhaps it is time to start making that killing? I know I would have taken advantage of that service.

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!