Higher CG Concerns With Flat Beds?!

[Four Wheeler]

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, CG 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 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

 

[WOODY2]

Anchoring it to the base isn't going to really change the vertical CG. That is a static figure of the amount of weight and it's vertical location.

 

[rruff]

I'm a newbie to these issues, so any tips or opinions much appreciated!

Can you give more detail regarding exactly what you experienced?

Trucks and SUVs can tip over without a load if you aren't careful how you handle them in an emergency. Poor shocks could certainly contribute. But I don't see the camper being that big of an issue. The weight isn't that high... and it's around 25% of your truck's unladen weight? Plus it gives you a more equal fore-aft weight distribution.

 

[crazysccrmd]

Did you already have the sway bar, shocks, bags, etc when you flipped it? If not then the sway from the sudden manuevering coupled with you're truck carrying over it's designed payload is more the issue than the height. The CG on a Hawk (unless loaded poorly) is forward of the rear axle and not excessively high given the pop-up design.

 

[MyNameIsMud]

I've added a sway bar, heavier duty Bilsteine 1500 shocks, and airbags to assist with stability.

I think you've done the right things already. Just stop driving like a stuntman and you'll be fine.

 

[MuleShoer]

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.

your statement has conflicts
mass produced aluminum will sit above the frame rails usually on 4” frame member that runs longitudina. This allows the mfg to mass produce a universal bed and less expensive
custom is usually in conflict with affordable but you can get them built to sit the camper lower. also your camper sitting on a stock PU bed is almost on the rails. The lightest and lowest flat bed that i found is SherpTek.com
located on oregon. But they cost $$$ however they are composite so very lite

as noted above the issue in stability is inherent to truck setup and driver response during an incident.

you did not mention tires. You need to run a stiffer sidewall E rated tire and a wider foot print.

 

[Buddha.]

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, CG 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 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

Are the airbags plumbed together or are they separate?

 

[rruff]

Are the airbags plumbed together or are they separate?

On that note, they need to be separate!

 

[Buckstopper]

Sorry to see what happened to you. My experience from having both slide in and flatbed (Hallmarks) the flatbed model has heavy utilities such as batteries, propane tanks, hot water heater and water storage tanks mounted a good 2' lower where the wheel well cutouts were on the slide in model so intuitively the flatbed model has the lower CG of the two.

I think you are on the right path to beef up the sway bar and shocks regardless which camper you get. Most campers max out the GVW rating of a 1/2 ton pickup especially when loaded with water, supplies and gear so these mods will buy you some stability. If you want to bring all your toys with you a heavier duty truck may be in order.

 

[IdaSHO]

Built correctly, a flatbed camper has a lower COG than that of a traditional slide-in.

You not only have more ability to bring heavy items lower, but also the control to spread weight left-right and front to rear.

Our custom camper is nose heavy by design and it VERY close to 50/50 left to right.
COG is very low as well. COG for the camper itself is right at the tops of the side compartment boxes.
COG for truck and camper I imagine is right about bed height, or even a touch lower.

These newer trucks are big on drivetrain/running gear and light on everything else.
Paper thin sheetmetal it seems, and a complaint of my own, but it certainly brings the overall weight and COG down.

 

[Nailhead]

CG is something that really didn’t occur to me until reading this thread. I’ll be setting this camper:

On this truck:

On top of this “subframe”:

Hopefully, being a 1-ton, it won’t be as tippy as that Toyota. Still, I think I’ll keep the sidehilling to a minimum.


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