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Flat Beds--COG Can Be A Problem!?

CG Center of Gravity Flat Beds Tundra FWC COG FWC Accident Stabiity Flatbed

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#1 ALLAN BRILL

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Posted 23 November 2019 - 09:20 PM

Greetings Wandering Brothers & Sisters.

 

From my sad experience (see attached photo of my FWC after accident), I can say that even without the approximate 5" lift flat beds generally require above my 2004 Tundra 4WD Double Cab stock bed, COG can be a problem.  My platform for the FWC raised the camper 3" above the sides of the bed unnecessarily, which I believe increased the COG height enough to make the swerve less controllable. I avoided a car swerving into my rig but couldn't control the resultant sway/instability. The oncoming, thundering 18-wheelers scared but avoided me despite the 3 blocked lanes!

 

I am considering a flat bed to replace the damaged stock one on my Tundra, so I can add boxes for storage & carry bikes/gas cans in front of my my current 2013 Hawk slide-in.  The mass produced flat beds I've seen sit above the tires, and raise the COG between 3-6 inches above the stock beds depending on model & different estimates.  As you can imagine, since I escaped the recent tip-over with little damage (though the camper was totaled and truck took substantial repair), I'm grateful and not feeling like risking anything like that in the future.  BTW I've added a sway bar, heavier duty Bilsteine 1500 shocks, and airbags to assist with stability.

 

SOOOO...anyone have any experiences, leads, expertise or understanding about these issues?  Have others you know of endured turn-overs as pictured below? I've been unable to find a mass produced or affordable custom flat bed that can actually anchor directly to the Tundra base & around the wheels, and thus keep the COG lower.  I'm a newbie to these issues, so any tips or opinions much appreciated!

 

Allan

 

 

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#2 klahanie

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Posted 24 November 2019 - 12:41 AM

Hello. Glad to read you were ok after that !

 

Question: Are you saying you didn't have a rear stabilizer bar on the truck before and if not is that a Tundra thing ?

 

If you are thinking to put bikes and fuel cans in front of the camper on the flat deck and then re positioning the camper rearward along with carrying more weight (stuff) in under deck storage boxes I don't see how that is compatible with, not wanting to risk anything like that in the future. That's not a criticism, just that I think all of those changes are going to reduce emergency handling.

 

On the flat deck, I'd expect it would be tough to find a stock one with wheel housings, esp for your vehicle size so a modification to a stock unit may be the answer. One thing with the "true", over the wheels flat deck is the underdeck boxes can be taller and therefore possibly carry more weight which does bring the cog down a bit (but adds to total weight). Anything you can relocate lower helps.

 

I haven't found a noticeable difference handling or tippy wise with our current flatdeck vs the previous F250 PU with the same camper but this newer vehicle is a much heavier and longer wb model. The higher camper position is offset somewhat by a 3-400 lb aux fuel tank between the frame rails, all the junk we carry in the under deck boxes and the relocating of some of the camper items like LPG and water storage.

 

That said, accidents can happen to anyone. Hopefully you've had your last. :)

 

One other thing, with a factory PU box repairs might be easier, in terms of insurance and repair shop. Repairs on custom ... maybe not.


Edited by klahanie, 24 November 2019 - 12:42 AM.

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#3 Wango

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Posted 24 November 2019 - 02:18 PM

When i began doing the leg-work for our present setup, i had some initial concerns regarding cog.

My friends have may flatbeds on their work trucks and i had been around them to see how loads were managed.

Our camper was built with the vast majority of the load in front of the rear tires. The outside boxes contain our house batteries, chains, fluids and recovery gear, again most of which riding in front of the tires. 

The suspension work was all geared towards controlling sway as well as loads. 

After many thousands of miles/trails i can say that for the most part, sway has been somewhat mitigated, but have still felt it at times, mostly off-camber, heavily rutted surfaces. Even as light as these campers are, comparing to other rigs. They can add sway. 

We are looking into our next build(it's an addiction) and one thing we are seriously considering is a cab and chasis truck to start with, just to lower the bed height.

All of this being said, if i had to choose between a flatbed on a truck or a regular truck bed, i would take the flatbed 10 out of 10.

Good luck going forward, and very sorry about your accident. Thankfully your ok.

w


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#4 ntsqd

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Posted 24 November 2019 - 08:20 PM

Every time I've pondered the design of a flat bed specifically for a camper I end up lowering the deck as low as it can go. Which creates wheel-wells in the deck, making it no longer flat. I'm OK with that because of what it gains me in reducing the COG. With good jacks the camper does not have to slide between the fender-wells, It can go over the top of them before being lowered into place. 

 

Lately my thinking has been no bed at all. Just a platform that the camper sits on bolted directly to the frame. Included in the platform structure will be the anchor points. As I'll likely be working with a pick-up chassis that platform will bolt to where the bed bolted to. Only. Then I'll in-fill under the camper and around the rear tires with storage boxes.

At least, that's my current train of thought....


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#5 ski3pin

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Posted 24 November 2019 - 08:42 PM

The few times I let myself dream of and design a new truck and camper for us, it is right in line with your thinking.

 

Every time I've pondered the design of a flat bed specifically for a camper I end up lowering the deck as low as it can go. Which creates wheel-wells in the deck, making it no longer flat. I'm OK with that because of what it gains me in reducing the COG. With good jacks the camper does not have to slide between the fender-wells, It can go over the top of them before being lowered into place. 

 

Lately my thinking has been no bed at all. Just a platform that the camper sits on bolted directly to the frame. Included in the platform structure will be the anchor points. As I'll likely be working with a pick-up chassis that platform will bolt to where the bed bolted to. Only. Then I'll in-fill under the camper and around the rear tires with storage boxes.

At least, that's my current train of thought....


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#6 Vic Harder

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Posted 24 November 2019 - 10:00 PM

The few times I let myself dream of and design a new truck and camper for us, it is right in line with your thinking.

 

+1


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#7 JaSAn

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Posted 24 November 2019 - 10:29 PM

The few times I let myself dream of and design a new truck and camper for us, it is right in line with your thinking.

 

+2

Great minds think alike.

 

I'm thinking that when the wheel wells rust out on the Ram pickup box (a problem in Minnesota), I'll pull it and do ntsqd's  design.

Should lower the CG as the batteries, propane tank, tools, recovery gear, et.al. will be lower (and outside the camper).

 

jim


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#8 Durango1

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Posted 25 November 2019 - 01:59 AM

We are looking into our next build(it's an addiction) and one thing we are seriously considering is a cab and chasis truck to start with, just to lower the bed height.

Totally agree on looking into a cab and chassis, Wango. The design possibilities are greatly increased as long as you can live with lower trim options. For example, our 2018 Ram Chassis Cab (in the regular cab model) didn't come with the Laramie trim! BOO-HOO!


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#9 Kolockum

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Posted 25 November 2019 - 04:36 AM

This has opened an interesting conversation. I have long dreamed about flatbeds but never liked the significant bed raise required to to achieve them due to the cost of COG. I keep coming back to a modified flatbed with wheel arches.

 

I have always thought that if I go for broke and make a flatbed then I would incorporate components such as water/grey water and propane tanks into the flat bed to lower COG and then have quick connects to attach them to the camper. 

 

x2 glad you're ok.


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#10 ALLAN BRILL

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Posted 25 November 2019 - 02:12 PM

Many thanks for the thoughts and experiences...& well wishes!  I'm pouring over these issues, continuing to look for a workable low-CG solution for a non-DIY person that's affordable.  Any further ideas appreciated and will report any good finds!

 

BTW, the 2004 Tundra to my novice understanding has only a stock/light duty front anti-sway bar, and installing a rear one with all that's there including my Billsteine 1500s & air bags is an expensive custom job.  I've also been advised that the rear sway bar may be overkill with the airbags.

 

And thanks for the point about the problem with moving the camper back some inches for gas cans/bikes front storage, also  increasing instability.

 

Below are discussions of aluminum flat beds and CG from expedition portal.

 

Happy and safe travels!

 

Allan\

 

 

https://expeditionpo...d-trays.203882/

 

https://expeditionpo...options.169565/


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Also tagged with one or more of these keywords: CG, Center of Gravity, Flat Beds, Tundra, FWC, COG, FWC Accident, Stabiity, Flatbed

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