Roll Cage for an XJ

[jeepnchris]

Hi,

I am new to this list. I am in the process of building a roll cage and an exo on my XJ. I am looking for any direction that you guys could point me in regard to mounting the main hoops to the "frame". I am concerned that if I connect these hoops to the "frame rails" they will sheer off in a hard roll - like an endo. I will be competing with this Jeep. I look forward to being active on this list. I live in Charlottesville, Virginia.

Thanks in advance!
Chris

 

[XJZ]

Welcome Chris.

There's already been a great deal of discussion about rollcages on the forum, quite a bit just recently, do a search and you'll have a wealth of some great info.

 

[jeepnchris]

Maybe I am asking the wrong question. I did review the other posts and replies but could not find anything that would give me the strenght for a high impact roll over. I was wondering if anyone has any ideas on how to connect the roll cage to the "frame" so that it would not bend or sheer off in a roll over. On a framed vehicle, I would weld the bars straight (as straight as possible) to the tops of the frame rails to give the DOM tubing as much strenght as possible. I dont want it to bend. This Jeep is not driven on the roads.

Thanks!
Chris

 

[CRASH]

Maybe I am asking the wrong question. I did review the other posts and replies but could not find anything that would give me the strenght for a high impact roll over. I was wondering if anyone has any ideas on how to connect the roll cage to the "frame" so that it would not bend or sheer off in a roll over. On a framed vehicle, I would weld the bars straight (as straight as possible) to the tops of the frame rails to give the DOM tubing as much strenght as possible. I dont want it to bend. This Jeep is not driven on the roads.

Thanks!
Chris

If you try this, the A pillar ends up right between your legs, where the steering wheel once lived.

Did you see this thread: Cagey

I think the way these pillars are connected to the frame is pretty damn strong. The C and D's could be moved in about 4 inches and come in right above the frame rail, if you wanted to sacrifice the room inside.

CRASH

 

[jeepnchris]

Crash,

I like your cage, nice work. I am not concerned about the space lost with moving the c and d as well as the b to the middle more (over the "frame rails"). I am concerned about the front ones. I didnt see where you tied the a,b,c to the frame. Is it tied into your rocker/rail guard? I am concerned at connecting (through the floor with a j) the a to the frame. I have seen some people have that bar crush on them - didnt move off the frame rail - that was on a framed jeep, this is an XJ, do you think that the DOM (1.5" .120 wall) tubing will bend before the frame splits or sheers if it is connect with a j on the front pillar? Am I just trying to be too strong? The back idea looks great. I will also have an exo on this vehicle.

Thanks!
Chris

 

[CRASH]

Look all the way through the thread, there are more pics. The frame is reinforced, and the kickers hold the tubing whre it goes through the floor.

I feel the J hook is a good compromise. Before teh tube goes through the floor, it is welded to as plate inside that picks up the frame rail from the top. It is also welded to the wheel well in a couple of spots.

I really don't think it's going anywhere. But, as with anything that's prototyped, time will tell. See my comments at the end of the thread about trying for too much rigidity,

CRASH

Crash,

I like your cage, nice work. I am not concerned about the space lost with moving the c and d as well as the b to the middle more (over the "frame rails"). I am concerned about the front ones. I didnt see where you tied the a,b,c to the frame. Is it tied into your rocker/rail guard? I am concerned at connecting (through the floor with a j) the a to the frame. I have seen some people have that bar crush on them - didnt move off the frame rail - that was on a framed jeep, this is an XJ, do you think that the DOM (1.5" .120 wall) tubing will bend before the frame splits or sheers if it is connect with a j on the front pillar? Am I just trying to be too strong? The back idea looks great. I will also have an exo on this vehicle.

Thanks!
Chris

 

[Letterman]

Ok so I had this thought last night, what if you got the front bar out of the way and used an Exo in front only do you think this would be too week?

So get rid of the inside A Pillar here:

Like this:

or even better like this:

and tie it in to an Exo here and the other side:

this would get rid of the Head knocker/knee knocker bars but keep the B-pillar for stranth.

Maybe?
I am still thinking on how I am going to do this.
Any thougths?

PS sorry if I am High Jacking this thread, it is sort of on topic

 

[Lupine]

What's not shown in that last thread is the outside portion of that A-pillar. There will be an additional A-pillar on the outside, that runs from the roof rack, down through the fender and will terminate at the 2x6 that forms the rock rail. I wanted to continue the ladder theme all the way down.

This will likely be made of .095 wall to keep the weight down.

CRASH

 

[JP]

I've been lurking around these cage posts for a while, so lets me see if my thoughts make sense. Stealing from many good ideas, one thought is to basically 'frame' the XJ's frame. This would be an exo/internal cage with the exo consisting of the 'a' pillar, a roof halo welded along the gutter mounts, and a 'd' pillar. Both the 'a' and 'd' bars would hide behind the fender giving a clean look to the exterior. The inside would be similar to Goatman's welded 'a' pillar w/ no down bars and attached to the seatbolts at the 'b' and 'c' pillars. Make everything as tight to the body as possible and attach the exo and internal through the insert rails like Farmermatt's rack tie ins.

I guess my question is how important is allowing for cage delfection in the exo? I making a big mistake by wanting to weld to the gutter mounts for rigidity?

thanks, Jeff

 

[Beezil]

JP....

hard to say.....I'm thinking it probably not worth the effort to make the roofline "one" with the cage, as I don't think much of the upper unibody has much to offer in terms of stregth that the tubular rollcage doesn't have already by itself....

IMHO, I think its best to concentrate on building a sound cage with triangulation, tying it into the framerails as well as you can, and let the rest of the body kinda' "float" within the form......

however, i do think there are some locations that worth tying into....for one, the upper seatbelt mount (the goatman method) and you can also "capture" the roofline with a steel-rubber "sandwhich" as you are passing through to the exo from the inside....not to make the cage stronger, just a method of "joining"

Crash is going after welding the sheetmetal of the roof to the vertical tubes that pass through.....

I am skeptical about how much real "strength" is gained by doing so.....and even if it wasn't done for strength reasons, I believe it will eventually tear....

but that would be "par for the course" for that jeep, not like it would shock any of us.....cracking and tearing is a design element used in the URF vehicle....something about "stress relieveing benefits" or some phooey.....

 

[poomba]

I am skeptical about how much real "strength" is gained by doing so.....and even if it wasn't done for strength reasons, I believe it will eventually tear....

but that would be "par for the course" for that jeep, not like it would shock any of us.....cracking and tearing is a design element used in the URF vehicle....something about "stress relieveing benefits" or some phooey.....

And here I thought relieving stress was the reason we took the jeeps out in the first place! :laugh3:

 

[Fore Wheeler]

lets talk about the exo thing. what's the purpose? it adds weight, it adds height, and if you build an internal cage that will support the weight of the Jeep in the event of a roll over why have one? to protect the replaceable body of a cheap XJ? sounds like the cons out weigh the pros.

I'm going to have a cage by winterfest, myself and a buddy of mine (who builds stock cars) are going to start the first of the year. The attached image has a unique idea for the front hoop, look at the lower hoop. would this be an easier way to get that over all front 'a' hoop to fit snugly and beable to do more welding out of the vehicle?

How many have put a cage in with the full interior? I want to retain my head liner and plastic interior parts. good idea or bad?

 

[JP]

I like the lower front hoop idea ForeWheeler. It also gives another brace for the 'a' pillar under the dash which could add in strength. Mostly my point for the minimal exo would be to give some protection to the roofline in a slow roll or tip over situation and allow me to get easier entrance (i'm kinda a large fellow) without the interior cage legs. If I can live with the leg obstruction I would probably just build and interior cage and some "rock rails" for the roof line.

 

[2offroad]

i have a full cage with full interior, but it is bolt in and nobody likes it but me.

 

[jeepnchris]

I want an exo (I am removing the doors etc...) for sliding against rocks and other things without getting hung up. The exo that I will build will basically be tubing going from the front to the rear. It isn't that much extra weight. I will not have anything coming out of the roof.

Chris

 

[Fore Wheeler]

i have a full cage with full interior, but it is bolt in and nobody likes it but me.

What? the fact that it's bolt in or that you have interior? if its cuz you have interior, why don't they like it? I think the sound from a interiorless jeep would suck, plus while wheelin in the winter you'd be losing alot of insulation from the head liner, and I'm a whimp and need it 75*. the total weight of the interior isn't that much to really worry about, and I am leaving my leather, unless my wife wants if for her XJ, hmmmm, a sport with leather, might have to do that.

 

[2offroad]

What? the fact that it's bolt

http://www.naxja.org/forum/showthread.php?t=14146

 

[XJZ]

lets talk about the exo thing. what's the purpose? it adds weight, it adds height, and if you build an internal cage that will support the weight of the Jeep in the event of a roll over why have one? to protect the replaceable body of a cheap XJ? sounds like the cons out weigh the pros.

I'm going to have a cage by winterfest, myself and a buddy of mine (who builds stock cars) are going to start the first of the year. The attached image has a unique idea for the front hoop, look at the lower hoop. would this be an easier way to get that over all front 'a' hoop to fit snugly and beable to do more welding out of the vehicle?

How many have put a cage in with the full interior? I want to retain my head liner and plastic interior parts. good idea or bad?

I was thinking along the same lines, but planned on using the typical "A" hoop, and have the tube that goes along the top of the dash just go underneath it instead. That way it's out of harms way.

It might have to have a few slight bends in it to get around the heater, tranny hump, whatever else is under there and to keep it away from the knees etc. Might even have to bolt that tube in, in case you have to get under the dash.

 

[FarmerMatt]

Here's a pic of how I tied the "A" & "B" pillars to the frame. THe top plates extend across the frame rails with 3/16" plate & are welded into the floor board. The tube gussets to the frame are welded directly to the bottom of the floor plate & than welded to a plate on the frame. This speards the loads out to a greater area. If you look at it down the frame rail it creates a triangle between the floor plate, gusset, & frame rail.

Matt

Frame tie in's

 

[Renegade Jpr]

Just a quick question, Im building a interior cage for my XJ and would like to know how I would go about painting it once its welded up inside the XJ?