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Designing a cage for a DD.

12K views 27 replies 15 participants last post by  SHADY 
#1 ·
My truck is getting pushed more and more to its limit and sooner or later it'll go over (hopefully much later though). I really want to get a cage in my rig, but the problem is, every caged rig I have been in has been a nightmare to get in.

My truck is daily driven and often times there are people sitting in the back seat. I know a line has to be drawn somewhere for protection/function and ease of movement. I've learned that triangulation is key; but for a DD rig what can I get away with.

Right now, I don't want a cage that can handle multiple rolls, just something that will keep me safe if I ever do flop. Basically what I'm trying to get to here is that if I ever roll my rig, the truck is going to be done. I don't care if the body is totaled as long as my passengers and I are safe.

Now... design me a cage :toothless No really, I'm trying to figure out what cross bars I would need, etc.
 
#2 ·
I asked myself this same question before building my exto cage (pics on request)... which has a rather inconvenient (for back seat leg room) X right through behind the front seats, which supports the top of the cage to the frame (and of course triangulates) I'm satisfied with it and i think it'll be good in case of a roll (maybe i'll roll it over on video just to test it next time i'm out wheeling/making youtube videos, any votes?)

anyhow, you're going to have to do at least one / bar behind your seats, and the "roll bar" portion of the cage will have to have a couple braces going backwards to the frame in the rear as well. if you connect it to the chassis (as you should) and it is an interior cage, you have to attach it to the body as well incase the body comes off. i've done this in friends' trucks by running a piece of C channel (or some other metal) between the bottom 2 most points of the "x" bar, about a half inch above the floor.

my personal recommendation is build an exto cage as close to the body as possible, and solid mount it to the body as well, in as many places as possible, also solid mount the body to the frame. that way everything will stay together as one. and i like exto cages because they don't take up valuable interior space (im 6'2 and i hate hitting my head on roll cages)

another plus to the exto cage is it will save your truck in case of a roll, but you stated that is not a concern.. but it's at least an added bonus.
 
#5 ·
I'm not big on exo's on fullsize rigs. I've yet to see one that I really liked, and plus that takes away from the clean street ride I have going on. Flop your truck though, I want to see it in HD! :popc1:

Why not go with the S&W Racecars 10-pt kit? You can add on a "family cage" to the back, similar to what JBG sells, instead of the rear kickers if you want to use the rear bench seat. I have no problem crawling in & out of my S&W cage, and I'm old & fat. Even my 70+year old Dad can climb in over the door bars. There are a few 92-96 Broncos with this cage kit here in the rollcage thread. The dashboard sticks out more than the 80-86 models, but that still doesn't hamper your entry/exit. JSM84
The S&W kit is a great price, but those cross bars are taking away from the ease of entry/exit; I'm sorry, but I don't see your 70+ year old dad climbing through the jungle gym seen here:




Now before anybody starts to point out the flaws in my design let me note that it is not finished yet.

When I designed mine it was with the same goals in mind. So I made sure to tuck the cage as close to the body as possible. For a DD 1.75in .120 wall will be fine. I know that this has been debated over and over but my preference for the 1.75 over th 2in is simply for ease of use. 2in tube gets a little bulky inside the truck with passengers. You have to ask yourself a couple of questions first. 1. If you roll are you worried if your bronco is trashed after. The cage is meant to protect the occupants not save the bronco in my opinion. 2. Its a DD so you need ease of access. 3. What kind of roll are you likely to have (high speed desert racing? Low speed rock flop?) You need to build accordingly. In a high speed roll you will need cross bracing behind the front seats. Triangulation is key in a good cage design.(mine isn't in yet so do critique my design yet, still building) If you are gonna run 4 or 5 point harnesses you will need a mount behind the seats though. The shoulder attachment should be no more than 4in above or below the shoulder to eliminate a spinal compression in a roll.

Remember that every bend in your design is a weak point in the cage. Where there is a bend you should gusset the bend(not done in mine yet either). The fewer bends in your design the stronger it will be. This is where for comfort you will have to make some compromises. Ideally you would make your cage look like a box but this make comfort suck. Any point where one tube runs into another the design should carrie through to the other side of the attachment point. Tie your cage into the frame of the truck to ensure that the body doesn't separate from the frame and cage and become a rolling death trap. Because it is a DD you can get the cage tie in kits from polly performance that you a leaf spring poly bushing to isolate road vibrations. Anyway here are some picks of the start of my cage(not completed) I will be adding the front portion that will run through the dash, center spreaders that triangulate to the rear corners, and a triangulation bar on each side. There will also be a lateral support between each of the legs behind the rear seat and the front seats. Still a work in progress but with having kids I feel much better having the cage.
I agree with your points mentioned. The cage wouldn't be seeing high speed barrel rolls, more like slow tippy flops. By flops, I mean one time deal. More than likely the truck wouldn't come out in one piece. As long as my occupants and I are alright, the cage did what I want it to do. If I ever flop or roll and the truck can't hold its shape, its time to move onto another project. I never want to have to test the cage, but I want it for comfort on the tippy trails and peace of mind knowing I'll be okay if shit hits the tank.
 
#3 ·
Why not go with the S&W Racecars 10-pt kit? You can add on a "family cage" to the back, similar to what JBG sells, instead of the rear kickers if you want to use the rear bench seat. I have no problem crawling in & out of my S&W cage, and I'm old & fat. Even my 70+year old Dad can climb in over the door bars. There are a few 92-96 Broncos with this cage kit here in the rollcage thread. The dashboard sticks out more than the 80-86 models, but that still doesn't hamper your entry/exit. JSM84
 
#4 ·
Now before anybody starts to point out the flaws in my design let me note that it is not finished yet.

When I designed mine it was with the same goals in mind. So I made sure to tuck the cage as close to the body as possible. For a DD 1.75in .120 wall will be fine. I know that this has been debated over and over but my preference for the 1.75 over th 2in is simply for ease of use. 2in tube gets a little bulky inside the truck with passengers. You have to ask yourself a couple of questions first. 1. If you roll are you worried if your bronco is trashed after. The cage is meant to protect the occupants not save the bronco in my opinion. 2. Its a DD so you need ease of access. 3. What kind of roll are you likely to have (high speed desert racing? Low speed rock flop?) You need to build accordingly. In a high speed roll you will need cross bracing behind the front seats. Triangulation is key in a good cage design.(mine isn't in yet so do critique my design yet, still building) If you are gonna run 4 or 5 point harnesses you will need a mount behind the seats though. The shoulder attachment should be no more than 4in above or below the shoulder to eliminate a spinal compression in a roll.

Remember that every bend in your design is a weak point in the cage. Where there is a bend you should gusset the bend(not done in mine yet either). The fewer bends in your design the stronger it will be. This is where for comfort you will have to make some compromises. Ideally you would make your cage look like a box but this make comfort suck. Any point where one tube runs into another the design should carrie through to the other side of the attachment point. Tie your cage into the frame of the truck to ensure that the body doesn't separate from the frame and cage and become a rolling death trap. Because it is a DD you can get the cage tie in kits from polly performance that you a leaf spring poly bushing to isolate road vibrations. Anyway here are some picks of the start of my cage(not completed) I will be adding the front portion that will run through the dash, center spreaders that triangulate to the rear corners, and a triangulation bar on each side. There will also be a lateral support between each of the legs behind the rear seat and the front seats. Still a work in progress but with having kids I feel much better having the cage.



edit: Seat belt mounts will be attached to the cage too
 
#9 ·
if you only want it to last one roll, just put a roll bar under the b pillar and one above the back seat. bronco bodys are stronger than you would think, search for ecrist i think was his name. he rolled his like 6 times down a hillside and walked away and didn't even have a cage.

i'm gonna redo my cage, i'm just gonna buy the S&W cage. its got all the basics you need and with a little creativity you can improve it 3x with a little extra bracing and gusseting in the proper places. the x bar behind the seats is not necessary, but you may as well consider it the backbone of your cage. its your call whether your ultimate safety is more important than being able to get in and out of a seat you won't ever sit in.
 
#25 ·
he was very lucky tho...I saw that thing in person as I helped recover it. not pretty. then again he would have had to have one badass cage to withstand that roll too. fyi it he parted it and has not wheeled since to the best of my knowledge.


this was after the roof was highlifted back up to be able to sit in it. It was below the dash line


have fun digging your passengers feet out of that mess


on its lid

what it went down
 
#11 ·
personally, i feel that if you are going to go thru all the trouble of making a cage, you may as well make it strong enough to save the body. as long as the core of the cab is somewhat intact, you can put in a new windsheild, doors, fenders etc. i have had several friends roll their rigs pretty hard and because the cab and cage were tied together only suffered minimal sheetmetal damage. you can always cut a roof out of a junker, patch in panels, pound out windsheild frames. i'm not a fan of removable bars, the more you wheel your truck and twist it up the more it will tweak the cage and frame. good luck getting removable bars in and out for long, if its not a structural member than you will have better luck.
 
#13 ·
just thought i would add a few things, seeing Stan's sig shows that he gets up to speed and gets airborn, so if you roll at speed you are going to roll hard and you need a good cage. Do you plan on caging just the cab or the shell area as well? The problem with caging a bronco is because you can't have the normal cross-braced main hoop, because that would block the rear seat off.
alot of the cages i have seen in the roll-cage thread and a few in this thread have too many dead tubes (tubes that T into another tube creating shear point), you really want to have as very few as possible (really none if you could). Just remember that triangles are your friend ;)
And if you roll you will need to cut/weld almost a whole new cab on most likely, but you can limit how much carnage there will be pretty well if you tuck your cage tight to the outer body skin well.
For a FSB not being entered in races i would use 1.75" .120 tubing. If i was going to race it i would use 2" .120 DOM because bronco's are heavy and i would want to be safe inside the tubing requirements.
Also keep in mind you will need to borrow someones quality tubing bender, and you will need a big welder for penetrating the tubing well. As well as a notcher (Harbor freight notcher does great)
 
#14 ·
I agree with you on the 1-3/4" DOM. Can that cross brace or triangle that usually goes behind the front seat be moved to behind the rear seat? Or is that too far rearward of the main roll forces? Just to put it out there, I'm perfectly fine with having a bar that runs above the dash (either following the bottom of the windhield or following the line of the dashpad. I don't know how well a curved spreader would do there though).
 
#15 ·
whipped this up :D
I am trying to design the same thing for my brothers '89 bronco. It's his DD and we need a cage so were looking for the same thing.
This is the basics of what i was thinking. out of a good material this should do pretty good. Just don't endo it or anything :D
basically have a main hoop in the middle there and build off that. 3 roof cross pieces, a dash piece (i drew two lines, pick one. I havent looked at my brothers bronco well enough to know what would work without hacking it up), then you need rear support for the hoop so i decided to make a cage under the shell too, to support that.

So that is a 6 point cage. You might have to make subframes for the hoop and front two connection points, or bend them to hit hte frame. I haven't looked at that yet. I left out door bars since its a DD. If you want more you could add door bars, and cross brace the top of the shell cage... and just start throwing support tubes everywhere. oh and that is a optional window "V"... if you want gnar points, extra support so it won't collapse as easy and if you don't want another truck or truck tire coming into your face... but that shouldn't be a problem.
 
#16 ·
My back seat gets used on an almost daily basis between kids, in-laws, and friends so I didn't install the bar behind the front seats. On my 79, I made it removeable and found once I took it out it spent the rest of it's time in the garage. I have mulled over the idea of adding a removeable one it I ever add 5 points. I dont find my cage to be intrusive at all.



 
#24 ·
What ever you do will be better than nothing!!!

My neighbor told me last week that he really needs to get his cage built. This weekend he went for a mild run up a dirt road and this is what happened. He was lucky he or his wife and the 3 kids in the car were not seriously hurt




Makes me want to finish mine immediately!!
 
#28 ·
A good strong main hoop at the B pillar with a couple of rear braces is all you really need to keep the roof off your head.
Just remember the only thing worse than having no cage, is rolling your truck with a poorly constructed one fitted . Make sure you use the correct steel and bolt everything in properly & if you aren't sure of your welding ability get someone else to weld it for you.

Shady
 
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