TJ cage additions

[justin'sbig7]

a guy from the forums stopped down this weekend and we worked up a cage for his tj. it was an extremely clean install IMHO, hopefully he likes it too lol! i did it in bendtech and it worked out beautifully. the side vents are the only thng lost with this install, and the smaller side window defrosters are still functional. heres the pics:

http://i48.photobucket.com/albums/f214/justinsbig7/fabrication/006-8.jpg

http://i48.photobucket.com/albums/f214/justinsbig7/fabrication/013-2.jpg

http://i48.photobucket.com/albums/f214/justinsbig7/fabrication/008-6.jpg

http://i48.photobucket.com/albums/f214/justinsbig7/fabrication/003-10.jpg

http://i48.photobucket.com/albums/f214/justinsbig7/fabrication/019-1.jpg

http://i48.photobucket.com/albums/f214/justinsbig7/fabrication/023.jpg

http://i48.photobucket.com/albums/f214/justinsbig7/fabrication/022.jpg

http://i48.photobucket.com/albums/f214/justinsbig7/fabrication/027.jpg

nice tight fit to give as much room as possible
http://i48.photobucket.com/albums/f214/justinsbig7/fabrication/020.jpg

[limegreentj]

very nice! i know who it was! the windshield frame gives it away! lol

[tjblair]

Looks great man! you are alot neater than I was when I did mine, with the hole saw through the dash. lol I just hacked off the corner of the plastic.lol Did, or are you giong to tie in the front to the frame?

[justin'sbig7]

Looks great man! you are alot neater than I was when I did mine, with the hole saw through the dash. lol I just hacked off the corner of the plastic.lol Did, or are you giong to tie in the front to the frame?

no, after researching this quite heavily, it is recommended that you do not tie the frame in UNLESS you have the seats tied to the cage with a seat subframe. the theory behind this is that the body plates will create a "cookie cutter" effect on the bodys sheet metal. the plates will rip through the sheet metal very easily when sandwiched thru plates, this is also enhanced by the vibrations from a rigid frame mount and body flex around it. so in a bad roll the theory is that the body bolts can easily shear off or rip out of the body, and the frame plates punch through, you are bolted to the body that is now floating in the cage since the seats are bolted to the body. if the cage is just bolted to the body, in the event of body bolts tearing out of the channels, the body has a cage and your seats securely mounted to it.

this is just what i have found while checking out cage theory and makes sense to me. it may or may not be 100% correct but i can easily see the situations.

[tjblair]

So what if you tie in the front and rear??? I mean the main hoop is still tied to the tub.

[justin'sbig7]

anywhere the sheet metal is sandwiched with plates, and then anchored to the frame, it causes the potential to have a cookie cutter effect on the sheet. it will be magnified as the jeep flexes from off road use, the rigid mounts will hold while the body flexes around the mounts (kinda like crinkling a coke can back and forth). the center is bolted to the tub on one side and is not really tied to the frame.

[tjblair]

I get what you are saying. I guess what I am saying if you dont sandwich the tub, like I did on mine in the front I just cut a hole ran the cage straight thouugh to a piece of box channel welded to the frame.
What I was thinking of doing on the rear was running a tube straight up into the rear stock cage where it attaches to the wheel well, and unbolt it there. You would have to cut out a little of the tub around the tube so that the tub had enough room to move around a little. I don't know, I cant think of another way to do it. I am open to suggestions if you have any ideas. I guess I would like the cage to be tied to the frame on all four corners.

[Sycotik Skier]

so if your seats are not tied into the cage you shouldn't tie the cage into the frame? Am I understanding this right?

[justin'sbig7]

so if your seats are not tied into the cage you shouldn't tie the cage into the frame? Am I understanding this right?


brent, that is the gist of what i have gathered from some 4x4 fabricators.

jeff, what would keep the tub from sliding up the tube in the front of your jeep if the tub were to break away from the frame? essentially this is the issue, you would slide up out of the cage and be crushed. being bolted to the body if it slid up the cage when it broke away from the frame... i always liked the frame tie in idea as well, but after reading in depth on cages and forces and how the tube carries the forces it is mind boggling all of the theory on cage design :119:. i think a lot of these scenarios are getting quite extreme, i have only occasionally heard of a body breaking away from the frame, and i have seen some piss poorly designed cages hold up to some nasty rolls, but ... :087:

[Sycotik Skier]

from what I have read I'd agree. I think the proper way is to just tie your seats into the cage so your body stays with the cage. I can see what you're talking about with the cage punching through the body and crushing you.

[tjblair]

Yah, I hear you. Hopefully I never get in a really hard roll like that but I think that maybe in the future I will find a way to tie the seats in to the cage as well. mabye run a tube back from the down tube to the main hoop. And then a couple tubes across to mount the seats to. Somthing like you did on your new cage. I need new seats any way. lol

[justin'sbig7]

i hope i am not coming off as argumentative or condescending here as i am really not trying to. i am gonna tie my cage in to stiffen up the chassis since i have the seat subframe. i feel like the jeep could desintegrate around me and it wouldnt matter since i am in my own self contained cage. my old one was only tied in in one place before, but i had a seat subframe as well.

[village_idiot]

if you tie the seats into the cage, shouldnt you tie the harnesses in as well?

[Sycotik Skier]

assuming your seats are tied into the cage and your cage is tied into the frame at six points your sheet metal should only be there for looks. When you roll the body panels can disintegrate and your cage and seats and frame will stay intact.

[Deadman 94 xj]

All you frame guys and all your issues.... :overkill:

[Sycotik Skier]

yeah cause I'd much rather worry about a unibody :flipoff2:

[justin'sbig7]

if you tie the seats into the cage, shouldnt you tie the harnesses in as well?


yes

[CESCO]

All you frame guys and all your issues.... :overkill:

Good one!!!

that must be why I only have about 4' of my frame left under mine....

[dan58]

Nice work on the tube! My old TJ had a very similar cage, going right down through.

What makes me cringe is ALL of the extra work to tie into the stock cage. That couldn't have been more than another $75 in tube to have a full cage. Frame ties with the seats tied to the cage are the ticket. Couldn't talk the owner into doing a full monty cage?

[96greenxjjeep]

couldnt you do slugs that go thru the floor and tie to the frame and still have the body fish plates as well?

[justin'sbig7]

couldnt you do slugs that go thru the floor and tie to the frame and still have the body fish plates as well?

you still have a plate that is gonna punch thru the sheetmetal though correct? if you dont have a plate, what keeps the body from sliding up the tubes if it came loose from the frame?


theres lot of ways to skin a cat, but essentially cage is hooked to frame = body is weak point. you are tied to the body, let alons if you have stock seatbelts that some are tied to the frame and some are tied to the body.... cage is hooked to body= you are now in your own lil capsule. unless seats and harnesses are tied to frame, it appears, from info gathered from shops who build these for a living, to be that cage to frame ties are not a good idea without a seating subframe

[96greenxjjeep]

ic yea im getting it looks good by the way

[justin'sbig7]

Thanks!