I figured I would ask this question because I asked others and couldnt get a straight anwser.

I wanted to get a roll cage in my daily driver/ weekend warrior. Its no buggy, but it will come on its roof one of these days. I also wanted the cage because its a biggy heavy suv, and when it lands on its roof in a big wreck, I wanted the roof to stay up, and not smack me in the head.

Of course the cage is going to help in any kind of slow speed roll, any time I tip it offroading. Still going to lose the roof and the windshield since the cage is inside, but I would just sawzall the damadge off.

However if I hit something on road, hard, that has little give, will the cage just cause my passangers more harm.

Some one gave me the reasoning the the cage is not going to let the truck crumple, allowing all the force of hitting say a semi, tranfer over to me. I have a huge arb on the bumper, so I am probally fawked any way. The thing isnt going to crumple much with a heavy bumper, and a boxed frame.

The thing that made me want to invest in one is seeing this really weird accident on 495 in va. This elderly man had a moment, and drove off the road. He drove through 2 highway light transformers, missed about 4 or 5 huge poles, and ended up just ripping off every wheel. If he hit the center divide on the right instead; there would have been a whole bunch of crashed vehicles, and dead people.

I was going to get some racing seats and good harnesses to go with the cage, so we would stay inside it.

Thanks guys. :D

I would have to say from experience that a well designed cage inside of an enclosed body will probably help to save your bacon in the case of a highway crash.

Typically, when you go upside down in a highway crash, the windshield pillar(s) will fold back into the cab. If you install a cage inside of the cab it will lessen the chance of of the roof caving in around your (and your passengers) head. Just remember to make sure everyone is belted in securely. Oh yeah, use lots of padding.

From the fire wall forward is the clumple zone in a high speed frontal. People are mistaken when they think that bigger is safer. It's not always true. Suburbans and such do not do as well as you would think in a head on with something of equal size or a fixed object. There are MANY cars that the occupents are less likly to have life threatening injury.
My though is the less the vehicle can crumple around the passenger compartment the better. That's backed up by the vehicles that score high in crash tests.
A well designed cage is going to help that. A key to this is a brace from the A=piller to the B piller bars on the roll cage. This does two things. first is it helps protect in a side impact and second is in a heavy frontal it will help keep the front floor from buckling up and jamming your legs into the dash. Leg injurries are high on the list of problems in an accident. Problem is living with having to get over a bar on a DD. If you keep it low it will still add protection but make it a little more friendly. Most people will go low on the A-pillar bar and come up at an angle to the B-piller. The higher you go the more it it braces the floor.

I suppose I'd rather have a cage than not, but they say that you can do some damage when your internal organs slam up against your body cavity - and I guess that would be worse if there was no crumple zone to slow you down.

Bryan

Having a cage will help no matter what. A well designed one for that matter. Like they said before, the crumple zone is the area in front of the A-pillars (the engine compartment).
By leaving this area free of cage tubing, will help keep some of the impact from being directed all on you. But you will still have your internal organs bouncing around. That cannot be helped.
Newer vehicles are designed so the engine will fall away and down, out of the passenger compartment in a frontal crash. In older cars and trucks, the engine would sometimes get pushed through the fire wall and into the passengers legs.
You could design the cage to also leave some of the rear of the vehicle free of tubing for a rear crumple zone. For instance, leaving the rear cargo area in a Burb cageless, and only protect the areas where passengers sit.

Dean

i think a cage can do nothing but help.. mainly from helping to keep stuff from crushing you and keeping the area around you open..

this is the other thing.. and this is only my opinion.. but where do most high speed wrecks occur?? that's right, nascar.. their cages are internal and must be dom.. dom absorbs impact in those high speed crashes which is why it's used.. it doesn't make everything so rigid that your vehicle is now too stiff.. in slow rolls on the trails dom doesn't deform quite like a head on into the wall in turn 4 at 150 mph.. but in a hard ass roll on the trail it would probably show some of those properties..

bottom line i say you should feel much safer w/ a cage in anything.. nascar, trail rig, or corvette.. :D

look at just about every form of auto racing, they all run cages, and the vast majority of the time the drivers walk away from big wrecks. I dont think its just a coincidence. high speed or low speed your gonna be better off letting your organs bounce around inside you than having your rig crumple in around you and risking being crushed, trapped or both.

Dallas

Thanks for the replies guys. I have the same line of thought as you do, I just wanted some other to confirm.

:D

I have no doubt when a buddy rolled his CJ7 on the street, his full cage saved his life and additionally saved the Jeep from a lot more damage. BTW - this was multiple rolls at 60+ mph.

Originally posted by Bigger Valves
i think a cage can do nothing but help.. mainly from helping to keep stuff from crushing you and keeping the area around you open..

this is the other thing.. and this is only my opinion.. but where do most high speed wrecks occur?? that's right, nascar.. their cages are internal and must be dom.. dom absorbs impact in those high speed crashes which is why it's used.. it doesn't make everything so rigid that your vehicle is now too stiff.. in slow rolls on the trails dom doesn't deform quite like a head on into the wall in turn 4 at 150 mph.. but in a hard ass roll on the trail it would probably show some of those properties..

bottom line i say you should feel much safer w/ a cage in anything.. nascar, trail rig, or corvette.. :D

DAMN STRAIGHT

its pretty darn obvious, but it would have to be built correctly!

Originally posted by StinkBug
look at just about every form of auto racing, they all run cages, and the vast majority of the time the drivers walk away from big wrecks. I dont think its just a coincidence. high speed or low speed your gonna be better off letting your organs bounce around inside you than having your rig crumple in around you and risking being crushed, trapped or both.

Dallas


I think this is debatable, unless you're wearing a 5-point harness, full helmet, and hans device during your commute! :D

Crumple zones are meant to absorb alot of the energy that would otherwise be transferred through the frame and into the passengers bodies. If you're car doesn't crumple, you're going to feel that energy. Of course cages will improve your chances of surviving a rollover on the road, but we're talking about crumple zones here, of which the roof is not.

I am planning a cage for my rig, hopefully done by spring, and it's a DD rig. I'll wholy acknowledge that a stock ZJ may fair better in head-on collisions, and I'll try my darndest not to be a part of one! :D Probably every other type of collision, the caged rig will be better for the occupants.

I donno Chis, as long as you leave the front crumple zone and cage the passenger compartment it should just prevent the passenger compartment collapsing and taking your legs with it. ;)

Let's see NASCAR, NHRA, IHRA, CART, F1, WRC, and SCCA are just a few sactioning bodies that REQUIRE cages! And I don't think you'll be going any faster than they are.

EDIT: 5 point harnesses would be a logical choice to go with your cage upgrade. Not doing so would be like throwing in a bigger cam and headers yet staying with a 2BBL carb, it just ain't right.

that's true Mike, good point. What I'm getting at is that anything you cage is something that won't crumple. This'd apply to folks that laterally brace/box their frames as well I'd imagine.

Originally posted by BJ On Roids


DAMN STRAIGHT

its pretty darn obvious, but it would have to be built correctly!

The only detractor to a closed cage, is if your body is not restrained properly and you impact the cage.

Make sure the cage allows room so your head will not pinball off the cage members. Cage padding is your best defense short of good design clearance.
Establish occupant handles inside the cage, or better yet inside the compartment where they have little chance to catch body parts between the cage and body, or ground.

Good seats and restraint systems are great, but the harness mounts need to be placed properly. Being able to cross arms and lock into the harness during a roll over is great (almost fun, except the thoughts during the delay time to impact), but only if the mounts prevent spinal compression, or ejection (submarine slide or popping out the top).

The factory belts are usually a good compromise compared to a poorly mounted harness (that sometimes can make the result worse). If you use a harness, make sure the mounts are correct (for both the seat and harness).

Happy Trails!

Does anyone have diagrams of the proper way to mount 5 point harnesses?

Originally posted by Pook
Does anyone have diagrams of the proper way to mount 5 point harnesses?

Every look at the manufacturer's websites? Good place to findout.

Originally posted by Ed A. Stevens

Make sure the cage allows room so your head will not pinball off the cage members. Cage padding is your best defense short of good design clearance.

Good seats and restraint systems are great, but the harness mounts need to be placed properly.

You can probally figure out its a Montero from the name. The roof hieght on this sucker in huge, so there will be no problem keeping the cage out of the way of every ones heads.

I will defenitly be getting proper seats, and harness to go with it. And wont be buggering around with the mounting.

:D

Your airbag system will not operate as anticipated with a cage (and definately that ARB Bumper). No way to know if better or worse, but it will not deploy at the speeds it was designed for by the manufacturer.

(This is what I do for a living, calibrate the restraint control modules to detect a crash and deploy at the right time.)

Originally posted by AlumCJ
Your airbag system will not operate as anticipated with a cage (and definately that ARB Bumper). No way to know if better or worse, but it will not deploy at the speeds it was designed for by the manufacturer.

(This is what I do for a living, calibrate the restraint control modules to detect a crash and deploy at the right time.)

Even systems that use a rapid deceletion sensor not located behind the bumper?

Originally posted by AlumCJ
Your airbag system will not operate as anticipated with a cage (and definately that ARB Bumper).

I dont have an air bag system, or abs. So I am not really worried about affecting any complex systems on the truck. Just the way it absorbs inpact.

After all these replied the cage will be the next thing on my list.

yes. the "single point" systems measure energy in the middle of the car (which the cage will have a drastic affect on energy transfer through the floor pan) and the multipoint systems (with accelerometers near the radiator) will be affected by the bumpers.

Originally posted by Oxjockey


Even systems that use a rapid deceletion sensor not located behind the bumper?
ARB is very on top of things and their bumpers are designed not to interfere with any forward mounted sensors or contacts for airbags.

I don't care what they say, it affects the system. On top of it or not, do they crash 100+ vehicles to prove out a system? (at 300 k a pop!) NO! Do they have CAE models of the vehicle to prove out the system? NO!

Im not saying they make the system better or worse, just different. I wouldn't add one of these bumpers to my DD, let alone a 100lb winch! Thats guaranteed to change something.

just my 2c. take it or leave it...but i suggest take it!

Definitely will affect the system, how much depends on the bumper and the vehicle.
My ZJ used to have 3 decceleramotors(sp?): one in the center console in the cabin, and one at each front corner under the headlights. The stock bumper fascia would give alot sooner than an ARB bullbar, and trip the decceleramotor.
Consider a head-on, corner impact, where both vehicles collide at their driver-side headlight. The non-ARB'd ZJ will trip the decceleramotor nearly instantly. The ARB bumper is built like a brick sh*thouse, and won't crumple at the corner; it's going to want to push the whole bumper into the vehicle. It will collapse at the corner (I've seen a couple ARBs after frontal collisions), but not easily and not nearly as quickly. I think the result of that would be delayed airbag deployment. Whether it's enough of a delay to matter is anyone's guess, but there's definitely a difference.

I think the result of that would be delayed airbag deployment.

I respectully disagree. I think the airbag would trigger faster because the energy will not be absorbed by the bumper as readily. Of course, we're talking milliseconds, but...

I also thought those sensors behind the bumper were 'intereferance' sensors that would detect bumper deflection.

Bryan

I was under the impression they're, at least in the ZJ, deccel sensors.
My thinking is that if the corner can't crumple, and cause one or two of the sensors to register a different rate than the other sensor(s), the bumper has effectively interferred with their operation.

This is a very interesting discussion...here is some of my input.

In a high speed rollover the cage will help...it's a cushion in case the A and B pillars fail to do there job.

But, when frontal collisons and crumple zones come into play it's a bit different. Consider this, when you install that bumper and that cage how much extra mass are you adding to the vehicle?

Since the mass of the vehicle has gone up, the kinetic energy of the vehicle is now higher then that of the stock vehicle at all speeds. The question is whether the crumple zones are able to handle that extra energy? In a vehicle that has a poor crash rating most likely, No. How the extra energy translates to the vehicle is impossible to tell without intimate knowledge of the vehicle design and cage.

To my knowledge the NTSB conducts crash test at 50% payload of the vehicle. By payload I don't mean GVWR, I mean curb wieght plus half the wieght capacity of the trunk, cargo space, bed...whatever. So, if the parts you add don't exceed 50% of payload in wieght then you are golden as your ride will most likely perform similar to crash tests. Exceed it and who knows what the damn thing will do.

NTSB tests are suspect in the first place, if you dont believe that go look at their roof crush requirements. Vehicles that pass with flying colors still have roofs that completely collapse in any rollover accident. You're right about the mass going up. Which is why I'd really only cage the area that is not supposed to crush. That way you're supporting the structure even with the added energy. Im going to totally ignore passive restraints in this arguement because IMO they do not function in modified vehicles. I've seen several high speed frontal impacts in modified 4x4s with passive restraint systems and in no instance that I've personally witnessed has the air bag deploy, at all.