My rollcage thoughts...

[Pete M]

I'll preface this off with why I'm contemplating this at all since my wheeling style tends to be more on the cautious side. I've seen more than one Jeep that did a light roll or a mild impact into a tree when the driver wasn't doing anything that could be considered dangerous. I don't fear sheetmetal damage, but with a roll the A-pillar deforms and the Jeep is suddenly either a total write-off or a convertible candidate. I really like keeping the rain/snow out, so I'd like to provide some protection for my roof structure. But I love the look of a stock MJ and have no desire to cover it all up with a jungle gym. Any dashed lines you see are bars that will be hidden behind the sheetmetal. It'll be more work that way, but I recently learned that I have access to all the tools at school, so I'll be doing all the work myself (except for maybe the final welding). Oh, and for anyone that doesn't know, my current rollbar and rockerguards and very strong and very securely attached to the frame.

 

So anyway, here is the basic cage. Just a simple hoop (tied back to the rollbar) and A-pillars (which are tied into the rocker guards).

 

 

 

But then I thought about protecting the front. The outer sheetmetal is easy enough to replace, but the inner stuff really isn't. As a plus, this would help give considerable strength to the A-pillars. The front down bars will be exposed and bolted to the bumper.

 

 

 

But I realized that there wasn't enough triangulation, so I added gussets and diagonals. The diagonals on the roof will line up with the down bars of the rollbar.

 

 

 

 

So when all is said and done, you'll only see this:

 

 

 

I also have plans for steel fender flares, but that's a topic for another day.

[BIGHEEP]

I have been thinking of doing almost the same cage on my MJ but, one difference is I was going to add tubes that go from the rear of the roof , down the side of the truck and attach to the rock rails to prtect the rear of the cab in a rollover.

Kind of like this.... (my add ons in orange)

[johnny quest]

the only thing i can see wrong with that added part is that it makes the truck even wider, so squeezing past trees or rocks will be harder....

[Pete M]

I've thought about a bar in that location (seen pics of 2 MJs that had gotten pinched in by trees at the exact spot) but I was going to go straight down from the halo to the rocker guards, meaning that most of the bar was hidden behind the sheetmetal and nothing can snag the trees. It was part of the next stage for protecting the rear. It's hard to see in the pics above, but there's a support gusset at the rear that ties into the rollbar to help keep the halo up.

Since much of the work will be done on campus, it will most likely be done in steps. I haven't ironed out all the details quite yet. :roll: and I can only imagine how much weight this will add to my already heavy truck. :D There has to be a balance between too much and not enough.

 

 

[DirtyComanche]

I'm with you Pete, I like the lines of the stock trucks. There's a couple XJs on naxja that have similar front internal cage work done.

[pingpong]

Your design is sound. I think a bar goingfrom side to side by the cowl panel will increase your strength a lot. Also for rollover protection, adding some diaganols that are higher in the center, will make a big differenece. When matt designed my cage that was a key part of the design.

 

Also windshield bars. In the event of a rollover, ther is a chance even with a well built and triangulated cage that the cage will deflect some. Thats why my rig has the diaganol in the B-pillar hoop.

 

Also a door bar is important. I know you want to keep your doors and keep it "street legal".

 

we can discuss this in length why I did certain things on my rig, most of it was function over form.

 

Patrick

[Cooter]

There is a point of diminishing returns here- I have done over 20 cages for CJs, XJs, Scramblers, ect, and I would say the added weight isn't worth it. Just go with your first setup, and you will be fine. If you use enough tubing to almost build a tube buggy, you would be better off just building one and hanging MJ sheetmetal off it like a prostocker.

[Pete M]

Ahh yes, diminishing returns. That's my big concern. Where do I draw the line? It's probably for the best that I can only do this in stages, since if left in a garage with all the right tools I might just keep going and going till I starve to death. :roll:

I've thought about using slightly lesser metal for the gussets and connections and leave the big stuff for the main bars. It'll all be DOM, but the large stuff will likey be 1.5" so maybe I can use 1.25" or even 1" for the other stuff.

And as much as I claim to be a function-over-form guy, it may be just my odd sense of form that allows that. :D All my engineering experience makes me think that the right design can be strong enough, yet not overbearing in weight or appearance.

 

I want protection against this:

and this:

 

 

but I don't want this:

 

 

Not that those aren't great looking Jeeps. It's just not what I want my 88 to be.

[Pete M]

Maybe I could make some parts of it removeable, like a windshield down bar.

[BIGHEEP]

 

:eek:

 

It looks like a rolling prison.

 

:D

[pingpong]

I know my rig isn't everyone style, but it works for me :D . We built mine out 1.75 x.120 DOM. The rock rails are 2x.250 DOM, and my windshield bars are 1.25x.120 DOM.

 

 

Some where in between Those cages ther is a good compromise. Have you thought about doing an Internal roll cage. Something to protect just the driver/passenger. Keep the looks but still provide enough protection to keep the jeep intact. That was my initial idea, but I got carried away.

 

 

Also tubing adds some weight, but not as much as ppl think. I am actually lighter now then I was before, but I also ditched a lot of unneeded weight like doors and most of my glass :brows:

 

 

BTW my rig took 250' of tube to build :eek:

[Pete M]

I love your rig! But I also love the original MJ lines. Plus there are laws around here that would make it difficult to park your rig at my house (everything has to at least look street legal and running).

I'm not too worried about my head (the rollbar should be adequate to keep me alive), I worry that a mild mishap will destroy the one part of the truck that's hardest to replace in any sort of proper manner, the A-pillar and windshield frame.

Jeep on!

--Pete

[pingpong]

Believe it or not, if I added mud flaps, an outside rear view mirror, and removed my windshiled bars, I would be street legal :banana: I still have functioning lights, and wipers, and horn :brows: By the VA state inspection law I would "technically" be legal. Even the bumper height if I changed the weight class of my truck :eek: This is not saying that I would want to try and drive it around

[Cooter]

From what I have seen, the A-pillar is the most vulnerable on the XJ/MJ. Protect them, and you'll be good to go. :cheers: