How good is a body mount roll cage?

[Johnnyb]

I have a six-point, cross-braced cage, pretty standard compared to others I have seen.

My question is: It's mounted to the body and not the frame. Are we just fooling ourselves?

I'm pretty sure if I turned over while rock crawling, it would keep the chassis from crushing the front seat passengers, but how about accidents on the road?

-JB

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[gnsteam]

You are so right. We are fooling ourselves when thinking a floor only mounted roll cage is good enough. Especially when greater speeds come into play.

 

[MrT]

I see cages fly out all the time. Really I never have and I would love to hear or see an example of a cage ripping out of the body or stbbing through the floor enough to cause human damage.

 

[1970 Palmer]

The weakest link is going to break first. If the aftermarket roll bar/cage is stronger than the floor and body supports they will bend first. In this case the roll bar/cage will do just move the energy of the crash from the roof to the floor.

Many racing organizations have established regulations for adding roll bars to the pan/floor of a vehicle. They almost all require a 1/8" by 6" by 6" plate on the bottom of each roll bar leg, and a matching same sized plate on the bottom, sandwiching the (thin sheet metal) floor.

In anything except a high speed crash, I would think the current technology would hold up pretty well. The bars are overbuilt for the type of mounting we use in a EB.

Frankly, In my opinion, the real safety issue is driving/riding in any vehicle with a roll bar and not wearing a helmet is a safety concern. Even if the roll bar has the very hard energy absorbing SFI certified padding. A very small low speed accident causing your unprotected head to " just tap" a roll bar is a serious issue.

John

 

[ShoeSlinger]

My friend flipped his CJ5 with a bodymount cage. We had put plates on the underside. His cage saved their lives and held up. They were doing 55+, however frame mount is always better.

 

[okie4570]

Off road roll overs are usually slow and a well built, well attached to the body is fine imo. On the street and high way, yeah everyone is just fooling themselves.

 

[SteveL]

I've read if you're adding bottom plates below the floor make em a different size larger than the foot plates of the cage. If both are the same above and below the floor it can act as a punch and cut thru the floor over time.

 

[martinphoto]

I was in a 55+ mph crash in my last bronco. It had a body mounted "show" bar. Chrome, 3" diameter, not sure what it was build for. I had sandwiched the body with 1/4" plates. I believe it saved my life or at least great harm to my body. Was pulling a trailer that was way too heavy and tall full of tires. Got on the freeway and just merged onto the right lane when the trailer started swaying and decided to take me for a ride into the ditch on right side of the road. Hit my left shoulder on the pavement breaking it in 5 places. Rolled 1 1/2 times ending up on drivers side of bronco. The "roll" bar had pushed the pass side door post out about 8" The metal craftsman tool box I had sitting behind the back seat somehow managed to fly around and it hit me in the head. Mild concussion there. I also had a soft top on at the time which I asked the fire dept. not to cut but they had too to get me out as I could not climb out the pass side door with broken shoulder and collar bone. So as I said, it probably saved my life.

 

[No Hay]

I had mine welded to the frame, and after seeing aftermath pics of some that aren't, it feels better every time I drive it.

 

[Johnnyb]

All the opinions and advice are super helpful!
I think my cage is pretty strong. I had it custom built by a shop in Phoenix using 4130 chromoly 1.75" tubing. It mounts in six places, and is X-braced behind the driver and passenger, with a spare tire mount. The plates that mount it to the body are 3" by 5" and I think that might be the weak point.

Maybe I'll cut some larger plates to increase the surface area.

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[bronconut73]

If we tie our cages together at the floor with tube.....
Where each floor mounted tube has a horizontal tube tying it to the opposing floor mounted tube on the other side of the Bronco....
Wouldn't that make it way harder for the cage to push through the floor? There would be all those horizontal tubes running at the floor level connecting all of the vertical tubes of the cage.....

 

[Yeller]

If we tie our cages together at the floor with tube.....
Where each floor mounted tube has a horizontal tube tying it to the opposing floor mounted tube on the other side of the Bronco....
Wouldn't that make it way harder for the cage to push through the floor? There would be all those horizontal tubes running at the floor level connecting all of the vertical tubes of the cage.....

This is the easy answer. If really concerned still add a bar between the A and B pillars and mount the seats to that. I’ve crashed and been around a lot of crashed stuff with cages, correct the weak link is the floor but a simple spreader at the floor on the B pillar solves the punching through and oil caning ripping it out. Every Bailie cage is built this way for that very reason and has some horrific crash survivor testimonials to back of the theory.

 

[73azbronco]

I see cages fly out all the time. Really I never have and I would love to hear or see an example of a cage ripping out of the body or stbbing through the floor enough to cause human damage.

Please, show us just one. Not directed at you.


Exactly, there is zero science on cages being better if they are mounted to frame, make no mistake, you are silly not doing it if you race, otherwise, it's all about the odds, and I say, i have never heard of a cage ripping out of a body in any vehicle anywhere, ever.

Put another way, saying a cage bolted to floor is inferior is just wrong, how many bronco bodies have been ripped off the frame? If they have, they were unsurvivable accidents in any event resulting in that level of damage.

 

[73azbronco]

This is the easy answer. If really concerned still add a bar between the A and B pillars and mount the seats to that. I’ve crashed and been around a lot of crashed stuff with cages, correct the weak link is the floor but a simple spreader at the floor on the B pillar solves the punching through and oil caning ripping it out. Every Bailie cage is built this way for that very reason and has some horrific crash survivor testimonials to back of the theory.

Precisely, I added the brush guards or side steps welded to the frame, so I have side impact protection, plus full frame and cage protection. I would not want to go cartwheeling down the road at 90, but I'm not driving 90 nor getting into a situation that it could happen.

 

[Johnnyb]

Of course we've all seen this one, not a Bronco but still: https://youtu.be/IcHrkhHXoHo

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[MrT]

I want to add a couple thoughts on the matter. If you can tie you cage in to the frame by all means do it, of course it's prefered. What I don't like to hear all the time is that a bolt in cage is just for show. I have read this countless times over the years and it is factually bullshit. I would hate to see someone discouraged from putting a basic cage in their 4x4 because they won't be tying it to the frame so they think it's pointless. Bolt to the floor cages have saved many lives including mine, the guy that posted earlier in this thread and who knows how many more.
All rollovers are different. Some will turn a stock car into a pile of scrap metal, some like mine were pretty violent on the street at 50mph or so. If you want people to know that you think tying the cage is important then say so. If you want to tell people bolting one in is pointless you really shouldn't. Mainly because it's simply not true.

 

[Johnnyb]

The conclusions seem to be:

1. Any cage is better than no cage.
2. A larger mounting surface is preferable for body mount cages.
3. Frame mounted is better than body mounted, when possible.

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[73azbronco]

Of course we've all seen this one, not a Bronco but still: https://youtu.be/IcHrkhHXoHo

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to be fair, that body was ripped off by the tow vehicle, soooooo

 

[73azbronco]

The conclusions seem to be:

1. Any cage is better than no cage.
2. A larger mounting surface is preferable for body mount cages.
3. Frame mounted is better than body mounted, when possible.

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Correct, but no science exists, no data exists to support or deny any option chosen. Except no cage appears to be more dangerous.

 

[FordBronc]

https://www.youtube.com/watch?v=xB_yxa-WXt8

https://bcbroncos.com/shop/interior/roll-cages/75-00112-bc-family-roll-cage-for-early-bronco/

https://www.youtube.com/watch?v=nc-sEqxAHLo