exo-cages [Archive] - NAXJA Forums -::- North American XJ Association

meangreenjeep

August 17th, 2003, 15:52

I still think an exo is worthless without interior support members....

Give me some reasons why?

http://www.funtigo.com/go?i=i83715_14501.jpg

I ask this because after rolling mine 2 3/4 violent barrel rolls, the roof held up better than I could have possibly imagined (windshield was intact, rear hatch window was intact, myself and passenger were un-hurt). I truly believe that a well designed exo that relies on body bracing (by this I mean that the exo would actually bolt to the body) will not only help the overall rigidity of the rig, but would survive multiple rolls without substantial damage (as well as deal with tree and rock "rubs" fairly well. ) Granted, my roof rack, being bolted through the roof, using a spacer, to the interior "sub-frame" or uni-body was largely to blame (or credit) for this, but this just further proves my point...the uni-body is plenty strong (structure over material), but needs some help holding it's shape (exo that is dependant upon using the body for support.)

I actually agree with the interior supports, but don't think that they are mandatory for making a functional exo.

Kejtar

August 17th, 2003, 15:53

You got lucky... the impact hit it in the right spots... and if you wanna do it... why not do it right ?: )

meangreenjeep

August 17th, 2003, 16:00

For 2.75 sideways barrel rolls from the top of "Committed" on Ma Bell, on rocks that blew out the side windows, with no doors???

C'mon...seems to me that this was a good (if un-asked for) test of the XJ's ability to take a hit.

Beezil

August 17th, 2003, 16:03

without an interior form, there is no possibility for triangulation.

an exo is certainly better than nothing at all, but if yer gonna do it, DO IT!

at least start with an interior form, and if you want external protection, build outward....

meangreenjeep

August 17th, 2003, 16:06

And after you spend all that time/money/effort to "build the inside right", you go out and wheel, and it rolls, and it's STILL totalled and junk, because "everybody" said exo's were junk (which is why you did the inside first). If I had even a modest exo on it, it would not have been totalled. But it was, because it didn't have a straight panel left on it, even though the basic unibody was still OK

meangreenjeep

August 17th, 2003, 16:09

I agree with the triangulation...I just don't think this is the first priority.

Save the part that actually has the strength (the form/structure).

Rev Den

August 17th, 2003, 17:34

Meangreen..
As a distant 3rd party observer let me just say this...

Beezil has forgotten more about the XJ unibody than you or I will ever know. None is aurguing that an exo only cage will not work, they are saying that it would be better, much better, with trianglation. Materials do not have strength, shapes do. (beat you ALL to it) An exo without bracing is just a bigger box, sure, you may have room for that box to cumple before the XJ, but I am not sure i would want to take that chance.

It is your Jeep, and what you do is what you do, but I would take the advise given by Mr. Beezil very seriously.

JMHO

Rev

meangreenjeep

August 17th, 2003, 18:33

...the uni-body is plenty strong (structure over material),

I think I beat you to it. Structure beats material almost every time. But, maybe we should do something about keeping that form, or structure for more than one roll. Look again at the pic I posted...there's NO cage in there, and it's still square. Make no mistake, this was a violent 2 3/4 revolutions roll, from the top of a very large rock face, with lots of rocks to hit on the way down.

Beezil has forgotten more about the XJ unibody than you or I will ever know.

As much as I respect and admire Beezil's experience and work, I have to point out...did you actually go to my sight and look around? I have spent the last 18 years as a professional mechanic, as well as avid off road enthusiast. I was ASE cert in auto for 10 years (5 as master tech), and am currently an ASE cert master school bus tech. I don't normally tout crap like this (blahblahblah), but I just want you to realize that I'm not just some ninny who just bought his first set of Craftsman tools:rolleyes: and decided to play with an XJ.

My "argument" here is that an exo isn't "useless" without the interior re-enforcements. Are interior re-enfocements a good thing? Yes. Do they need to be built in a smart way, so as to triangulate the overall design? Yes. Do you need them before considering an EXO? No. But, I also don't believe in the normal school of thought for exo's (at least as far as XJ's, and other uni-body rigs are concerned). A smaller diameter tubed exo, with lots of exo to body attachment points, would make for a very strong XJ indeed. Add in the interior bracing, or triangulation of strategic points, and you have yourself a winner.

Kejtar

August 17th, 2003, 18:39

Don't want to come of wrong but a mechanic has next to nothing to do with creating structurally sound constructions whether they be auto body or exo or cage......

You're saying that you rolled multiple times with very little damage..... a good example to prove your theory wrong would be Goatman. All he did was fall over onto his side onto a badly placed rock which has not only dented his side at the roof in, but it skewed his top to the side.....

Also down here in SoCal someone has rolled at our last Jambo (I believe the proper term was the road ran out on him and he went nose down and over IIRC) and his top was all tweaked in all directions..... if that was crossbraced and triangulated... he might have been able to retain his rig... but it wasn't and I think he ended up starting over with a new one...

Kejtar

Beezil

August 17th, 2003, 18:45

Add in the interior bracing, or triangulation of strategic points, and you have yourself a winner.

that is essentially my point.

What Rd

August 17th, 2003, 19:02

Hey - you could always get lucky twice in a row, right?

Beezil - PM'd you

TOZOVR

August 17th, 2003, 19:04

Last Month I has the displeasure of recovering Archie and Martha after they rolled on Committed at Mabell as well. I watched the entire debacle from 15 feet above them. Same obstacle as Mean grean.

The truck merely flopped and was a complete write off...and it was a 2001.

http://www.authorizedvehicle4x4.com/MABELL/ROLL7.jpg

IMHO, if this truck had had an interior cage, I feel it would have been repairable (within the ins company's parameters), with just sheetmetal and minor fabwork to get it all pretty again. With just an External? Dunno.

What is my point? Every roll is very different.

rockwerks

August 17th, 2003, 19:20

I dont have experience with XJ's but do with baja's and yes to get the best performance from nerf, and race bumpers we always tied teh to an internal cage.....the rear bumper to the main support...teh front bumper to the front or windshield support..under the trunk area, the side nerfs to the main support and to the pan.....
If I get the chance to totally finish the MJ before MOAB it will be a combo of tube bed roll cage with exo front, gotta callin some favors with the locals, Ive heped over the last year or so!

kegcrawler

August 17th, 2003, 19:21

wow, thanks for all the good info and pics. i understand what you are all talking about when you say an exo isn't as strong without an internal as it could be with an internal. so if that is the case would you really have to build a full 8 point cage to achieve the triangle bracing that seems to be the key to the success of an exo cage, or could you just brace the exo internally but not have a full cage.
thanks,
KREGG

Rev Den

August 17th, 2003, 20:03

Meangreen,
I was not trying to infer that you have no knowledge....it is very apparent that you do. I was simply stating a time proven fact based on my own experiances on this board. True, I do not know you, and maybe it was unfair to include you in my assesment of Beezils knowledge. I ment no disrespect.

We cool?

Rev

mark

August 17th, 2003, 20:27

looks like its time to take a saw to that 2k1 that rolled, thats a perfect excuse to go topless and build a cage

Jump This

August 17th, 2003, 20:33

I'm not sure anyone rolls a jeep and does so little damage as to not at least think about starting over. The idea of having an exterior cage is to prevent from needing to start over again. So to that end, you need interior support as well. I don't think anyone who takes the initiative to build an Exo-gage would ever not take into account the nesc. interior work as well....
The point of an exo-cage is to save the exterior...
add interior work and your good to go (over and over again!)

xj92

August 17th, 2003, 21:05

The way I look at it, if I roll something, I'm going to start over no matter what, unless it's a rock buggy with only steel tubing all over the place. I want an internal cage to stiffen up the chassis in general and to protect me in the event of a rollover. If I were trying to save the Jeep, I agree with the others, I'd do interior AND exterior cage.

vintagespeed

August 18th, 2003, 00:06

The 2k1 should porta power out the damage & keep on wheeling with plexi windows. I mean common there's still a roof! As to the exo cage thing, NO it simply isn't going to provide the support in the 2.75 roll being discussed. Fact is, it probably would have caused more damage due to the tubing cutting into the body & smashing the windshield. An exo-cage is like a piece of bread with the center removed.......just a crust & if you move it side to side it'll flex all over the place. SAME THING! If you're so hard-core that you need an exo-cage in the first place then why not cut a couple holes in the sides and triangulate it? Are you hard-core or not?

meangreenjeep

August 18th, 2003, 02:56

We cool?

We are very cool. And as another pointed out, being a mechanic does not mean that you have the necessary fab/design skills to do this kind of stuff. I just wanted to point out that I didn't just start doin this stuff yesterday ;)

Hey - you could always get lucky twice in a row, right?

OMG:rolleyes: almost 3 full revs violently down a VERY steep climb, with no doors...and I'm just "lucky". Whatever. Do you drive your XJ on the freeway? Counting on luck to save your life if you roll? Or, do you think that maybe all those high paid engineers were onto something:confused: Look at Archie & Marthie's XJ pic (BTW, What were they thinking trying Committed with their DD:eek: I'll have to have words with him ;) )...the roof failed because the obvious encounter with a large rock took away the all important "structure" by creasing the metal. What if he had a well thought out exo member along the roof line, attached to the body in numerous places (to spread the sharp impact and avoid sheet metal creasing)? I guarantee that an interior cage would have resulted in it staying more square, and still totalled. An exo would probably have kept it from being totalled.

As I said earlier, I think interior bracing is a good thing, just not mandatory first. I will be bracing my interior after I finish with the exo...but a lot of my reason is that I wheel/twist it up very often, and it has 240K on it, so the body is a bit fatigued. But...I feel that the exo, going against the commonly accepted rule that only the bumpers and rocker guards offer mounting points, and actually using the already fairly strong body for support (through the body, with spacers, to the interior sub-body) is a sound one.

So far this has been fairly flame free...let's keep it like that please. I have been cruising this board for 4 years now...I just don't make lots of comments, til now:)

meangreenjeep

August 18th, 2003, 03:02

Are you hard-core or not?

Nope, just a poser:rolleyes:

I don't need an exo now...just want one. And I'm thinking outside the "box" so to speak.

JToffroad.com

August 18th, 2003, 03:29

Build a modest internal cage that is tied into the xjs body for you and your pasengers. After you roll the cherokee and it is totalled, then find anouther XJ with a blown motor (:you are only looking for a good XJ body:) and transfer all the good parts from the totalled XJ to the just bought one. Then junk the totalled XJ. The XJ is a throw away body (:some may not agree:). Once you roll the cherokee exo or no exo you will most likely have future problems (:wheel, door, etc.. alignment:).

JToffroad.com

August 18th, 2003, 03:39

Unless you are the fabricator, The used XJ will probably be cheaper then someone else building the exo (:unless he is you brother-in-law:). And if you are the fabricator of the exo; you can swap the parts from donner XJ to new XJ faster then you can built an exo (:That is build the exo correctly which means researching and studing the XJs unibody/body:).

JToffroad.com

August 18th, 2003, 03:45

So, in closing unless you are after the exo look (:added weight:) build the XJ, and wheel the XJ.
Just keep an eye out for the bargin XJ located in a field on the side of the road. Sooner or later you will need it.

TOZOVR

August 18th, 2003, 04:43

Originally posted by vintagespeed
The 2k1 should porta power out the damage & keep on wheeling with plexi windows. I mean common there's still a roof! As to the exo cage thing, NO it simply isn't going to provide the support in the 2.75 roll being discussed. Fact is, it probably would have caused more damage due to the tubing cutting into the body & smashing the windshield. An exo-cage is like a piece of bread with the center removed.......just a crust & if you move it side to side it'll flex all over the place. SAME THING! If you're so hard-core that you need an exo-cage in the first place then why not cut a couple holes in the sides and triangulate it? Are you hard-core or not?
Insurance totalled it...Archie and Martha sold it for the Buyback ($1500 with all mods removed)....Arch already has a built and caged CJ that sees extreme duty, they didn't need another that they were still makig payments on.

A fellow Jeeper bought it and we shall see where it ends up!!!

Flowers

August 18th, 2003, 04:58

What amazes me, is when people start thinking about an exo-cage to protect their prize rig with zero thought about the safety of the occupants.

Side Note: This is not a flame toward anyone posting on this thread.

Flowers

JToffroad.com

August 18th, 2003, 07:00

Has anyone thought about a fully tubed frame XJ? You know the race buggies with fiberglass pannals. A tubed XJ with fiberglass pannals. Best of both worlds I guess?

---------------------------------------
Jereme

JToffroad.com

August 18th, 2003, 07:03

You could use the XJs body as molds for the fiberglass.

rockwerks

August 18th, 2003, 07:25

What amazes me, is when people start thinking about an exo-cage to protect their prize rig with zero thought about the safety of the occupants

HMMM...like the egg concept.....if you protect the shell you protect the egg.....a very good exo cage will protect the occupants...if they have on their seatbelts.

Flowers

August 18th, 2003, 08:47

Originally posted by xjnation
HMMM...like the egg concept.....if you protect the shell you protect the egg.....a very good exo cage will protect the occupants...if they have on their seatbelts.

"Which came first the chicken or the egg? He was walkin' down the street and he broke his leg."

Beezil

August 18th, 2003, 11:03

an egg shape works well because an egg is a geometrically efficient shape.....

a square requires triangulation.

no one is arguing wether or not an exo would be better than nothing....the point is, if you are going to all the trouble, why not design and build something that has the greatest chance of survival in a hard roll?

as far as fiberglass.....

you ever seen what happens to fiberglass when it recieves a hard impact? fiberglass would be the LAST material I'd choose for side panels.

My cj-6 had a glass tub, and I was very glad to get rid of it.

fatwreck

August 18th, 2003, 13:36

I just thought I would throw in a picture of an exo-caged XJ that I rode in recently. When he tipped it into this obstacle, it was nice to have it....it was like having sliders for the upper portion of the body.

I have no idea how it would fair in a roll over, but I do know that I won't be doing this trail anytime soon because I don't have an interior or exterior cage.

http://www.projectxj.com/images/trail.runs/08.09.03-indy/images/IMG_2936.jpg
http://www.projectxj.com/images/trail.runs/08.09.03-indy/images/IMG_2960.jpg

Blix

August 18th, 2003, 14:07

What doesn't seem to be taken in account here is basic engineering: make it strong enough for it's environment. What type of protection were you looking for, Kegcrawler? If you want protection for your person in respect to some standard mudding and wheeling, then the unibody is probably enough, just don't expect it to protect you agian after it's been tweaked (basic material properties). Once the steel has yeilded it will never function properly again, and unibody rigidity will be lost at least at some level (hint hint meangreenjeep). If you want a high level of impact safety, such as race-spec, then an internal cage is the only way to go, with 1.75" tube at .120" thickness. If you were looking at more of a jeep protector for low speed rollover events, an exo will probably do, even though it has little structural strength. It would still need to be tied in to the unibody somehow though, at least at the pinch seam and somewhere along the roof. Else it will just parallelogram and hit the body.

-Or you could just get an inclinometer!

kegcrawler

August 18th, 2003, 15:40

well i am looking for enough protection that will keep me safe if i flop or roll my xj and i want something strong enough that if either one of those things do happen i can just get it back on all fours and continue to go, i don't have a crap load of money to spend in the first place but i do believe that if you are going to do something then you should do it right the first time. i am not the most hard core of offroaders but i like to do my share of wheelin and what i would love to do is to make an exo-cage and an internal if need be and just go out and have fun and then i don't have to be quite as worried about my safety or the xj, i mean i have no problem with rock rash i just don't have the time or money or skills to completely chop off the top put a new one on and no one would ever know like some people can. and working with a college budget it would be alot cheaper and easier to spend the money to protect what i got instead of screwing it up and then banking on just swapping everything to a new one, i don't have that luxury (heck i dont' even have another vehicle so if i total this one, i am going to have to take the nike express and walk every where, or bum rides). so that is my main goal for asking all of these questions. and if i do need an internal cage to do it right do i have to have a full 8 point cage or is there another way to do it?
thanks for all the help.
kregg

Jeepin Jason

August 18th, 2003, 15:50

Good thread, I really dig the exo on that black XJ.

I think I agree with meangreen's line of thinking, a well designed exo doesn't necessarily need a fully triangulated internal cage to work well in most cases, but it would need to be tied into the roof of the XJ, so that both structures strengthened eachother.

BTW, how 'bout some folks with both internals and exo setups post their pics? :)

meangreenjeep

August 18th, 2003, 16:08

What I'm thinking about is a "system" if you will, which can be bought and installed in sections, as your need/experience/journey to becoming "hardcore" (god I hate that stupid word) progresses. It would have the ability to be built upon itself, and added to, and replace "sections" as they are needed ("hardcore", hehehe).

Remember, unless you are tumbling down the entire side of a mountain, your chance of having a life threatening roll is MUCH worse if it happens at freeway speed...and I don't see us all rushing out to cage the inside of our rigs for that. Why? Because the factory engineers already built one for us!! We just need to keep it from getting creased and folded from sudden impacts with rocks. For 90% of the XJ wheelers out there, interior bracing is not needed. Notice I'm not saying that interior bracing is bad, or useless, or anything like that(I know that I even admitted that I will be doing just that to mine soon somewhere in this thread)...I'm saying that most don't need something that severe, when the body already has all this well thought out structure to it. Just protect what's there.

I just hope I can design and market an economical do it yourself system like I am trying to describe before someone else does.

Beezil

August 18th, 2003, 16:52

theres just no such thing as "needing just a little bit of cage" since no one has any control of how hard they might roll.

It is ridiculous to assume that anyones possible roll will be the best case senario.

if you've gotten to the point where you are thinking you need a cage, then dammit, design and build a cage FOR THE WORST CASE SENARIO!

meangreenjeep

August 18th, 2003, 16:58

Beezil, do you have a cage in any of your street cars, DD's, family cars?

MaXJohnson

August 18th, 2003, 19:43

I'm not a fan of exo's. I think if you want to do the kind of extreme wheeling that requires that degree of protection, maybe an XJ isn't the right vehicle to base it on. That is unless you build a tube buggy and skin it with XJ sheet metal or you have plenty of time and money to prove how far you can take the XJ design.

That being said, fatwreck's pic of the black XJ is one of the better looking exo-cages that I've seen. Build one like it. Tie into the drip rail at multiple points along each side. Maybe run some plate from the side uprights to the door pillars.

Then, on the inside, run a tube behind the front seats from a plate on the rocker rail diagionally to the opposite roof sil and another going the opposite way to form an X. Make sure the plates attaching to the channel sections at the rocker panel and roof sil spread the load.Do it again towards the rear. That's about all the interior structure you would need to have a killer exo-cage. The weak point would be the A pillars. Hard to put a X's pr diagonals there without screwing with driver visibility.

I could learn to love an exo built like that.
fatwreck's exo + meangreenjeep's tie-in's + Beezil's "build it to handle the task" attitude. :cheers:

MaXJohnson

August 18th, 2003, 19:47

By the way, meangreeny. You've mentioned how the XJ handles 2 3/4 violent barrel rolls and maintains it structral intregrity. There have been may pic on this forum and others of lesser rolls where the roof didn't do so good. And, not just the ones that smack a big arse boulder. It's good that your's held up, but there's no reason to believe that your damage is typical.

Beezil

August 18th, 2003, 19:47

no, of course i don't have a cage in my durango, because I think the odds of me rolling over aren't great enough.

If I thought they were, and thought I needed a cage, I wouldn't build an exocage before I would build a solid interior cage first.

I see what line of logic you were working on, but the analogy was facile.

good debate though......

xjaddiction

August 18th, 2003, 20:34

This thread is great!

What are the dangers involved with a DD interior cage like TOR's (tennessee off road), in an on road type accident. What I'm thinking about is side impact (even front impact) and the closeness of an interior cage with an un-helmeted head. Is padding enough? Or do you need a 4 to 5 point harness to keep you in tight?

Greddy

What Rd

August 18th, 2003, 21:42

OMG:rolleyes: almost 3 full revs violently down a VERY steep climb, with no doors...and I'm just "lucky". Whatever. Do you drive your XJ on the freeway? Counting on luck to save your life if you roll? Or, do you think that maybe all those high paid engineers were onto something:confused:

Whatever is right. You rolled and came out of it impressed with your Jeep's structural integrity and some ideas about how to build on it (or off of it). So do it. But don't try to kid yourself into thinking you weren't DAMN lucky. I rolled from a slow speed, first end over end and then sideways, so many times I lost count and have spent the last 21 years as a paraplegic - I wasn't so lucky. Whether you'll be lucky the next time is not something you can predict or control. You can prepare, sure. Control is an illusion, my friend.
As far as the engineers who designed the XJ, I'll bet you money they never intended their wonderful unibody design to withstand roll-overs or any other catastrophic force without deforming and thereby dissipating some of those forces. That's the way all automobiles have been designed since about the forties.

So far this has been fairly flame free...let's keep it like that please. I have been cruising this board for 4 years now...I just don't make lots of comments, til now:) [/B][/QUOTE]

I wasn't attempting to flame you when I posted originally - and am not now. It seems you're just a little defensive of your idea and may have misinterpreted my attempt at a light-hearted means of pointing out that you're going to go ahead and do what you have in mind regardless of what is said here - so do it. You might just get lucky again - perhaps even so lucky as to never find out how well an internally unsupported exo will hold up under various scenarios. I never meant to insult you - but you'd do well to be a little less sensitive.

vintagespeed

August 19th, 2003, 00:04

If you're looking for a good example of an internal/external functional cage 'system' check out Goatman's rig. Not only is everything else awesome & functional, the new inny/outy cage rocks! He DID cut some holes to tie it all together but I dont think he's worried about that.

KarmirXJ

August 19th, 2003, 00:29

Originally posted by vintagespeed
check out Goatman's rig. Not only is everything else awesome & functional, the new inny/outy cage rocks!

Well??? we got 4 pages so for and only have 3 dinky pics.... Common people, WE WANNA SEE PICS!:rattle: Pics are worth a 1000 words, so slow down the chit:lecture:chat and speed up the drawings...:D:D:D

meangreenjeep

August 19th, 2003, 02:48

I wasn't attempting to flame you when I posted originally - and am not now. It seems you're just a little defensive of your idea and may have misinterpreted my attempt at a light-hearted means of pointing out that you're going to go ahead and do what you have in mind regardless of what is said here - so do it. You might just get lucky again - perhaps even so lucky as to never find out how well an internally unsupported exo will hold up under various scenarios. I never meant to insult you - but you'd do well to be a little less sensitive.

Sorry. I'll try to tone it down.
;)