Factory rollbars are just a start...I did not understand your mounting method. You are not creating a possible fatigue area in your tub where the foot of rollbar contacts the floor and consequently a hole the size of the foot? The backing plate on the underside should be smaller or larger than the rollbar foot which may be what you have done. Just trying to get some ideas for my own cage....

Hank
88 YJ (sort of)

 

/wwwthreads_images/icons/tongue.gif You have it right on target, Hank....the pad is about 4" X 6" and replaces the captured nut which the factory uses to hold the tub on to the rubber pads. The pad welds to the original body areas, but also welds to a new vertical plate which goes just in front of the tire and fills the area inside the Jeep body member. There is an additional vertical plate on the inside which goes across at the step section of the body, and THAT is where the vertical areas of the rollbar attach, in addition to the bolts down through to the heavy pad. So what was have is a "bridge" from frame rail to frame rail that supports the tub and gives the rollbar something to stand on. The rear pads of the CJ rollbar will actually stand on the built-in storage box we have planned for the rear. We are going strictly two-seater on this vehicle, and since we are in CA, EVERYTHING has to be under lock and key at all times./wwwthreads_images/icons/frown.gif

CJDave
Quadra-Tracs modified While-U-Wait by the crack moonguy/wwwthreads_images/icons/wink.gif Quadra-Trac Team./wwwthreads_images/icons/tongue.gif/wwwthreads_images/icons/smile.gif

 

Hey CJDave need to run this past you and any other experienced rollbar users/designers/fabricators. Maybe I have a big misunderstanding of dynamics in a roll, If I do, be kind to me and set me straight.

The fatal rollover picture brought some new thoughts to my mind on the construction of the rollbar. Or better yet, a passenger cage, similiar to what most Indy type cars, specialty vehicles i,e, vehicles that have high probability of wrecks/collisions. In the rollover pictures, the frame and all the heavy parts of the jeep was removed from the passenger compartment. I realize that this was probably caused by old weakend connections rather than by design. but in a roll like this, would it not have some safety aspects to have the body with a full cage, detach and be seperate. A lot less structural strength would be required for the cage, and the probability of surviving this would go up. (Of course, occupant restraint would be required for any system to work)

My thought are to tie in to the frame just well enough to withstand the slow roll typically experienced during wheeling. But in the case of a severe roll as this one, let the passenger compartment seperate from the mechanicals, enhancing the chance of survival.

What do you think?

Enjoying Montana's Big Sky (& rocks & rivers & mountians etc, You get the picture.)

 

That was a harsh roll, pretty untypical, but certainly possible. In a breakaway situation, you would have to worry about flying debris. Which one would be better, the frame staying underneath the roll cage and getting mangled or the frame and running gear coming off and acting like a separate "vehicle", which could become entangled.

I was most concerned from the shape of the roll bar. I know the Scramblers have larger roll bars, but I'm going to reinforce mine anyway. A stout cage is the best protection, IMO, and I can certainly se the necessity for tying the seats into it. I was a little skeptical before, but this rollover has taught be a lot from analyzing (looking the pictures over piece by piece for hours) what's left. Never in my life have I seen anything that's made that much of an impression on my decision making.

JEEPN
'81 CJ-8 Scrambled!
GM151/SM465/NP205 twinstick/7" Lift/33" Swampers/REP 8000/RS9000's/Scout II D44's F&R w/4.10's & Lockrights

 

JEEPN I don't understand something that you said If the roll bar was attatched to the frame which I think would in turn attatch the body to the frame why would it be important to attatch the seats to the roll bar system ?

 

My roll bar will be tied into the frame, but it'll attach to the body, then under the body there will be tie in mounts that go to the frame. There is the possiblity of the bolts breaking or pulling through whatever material they're attached to. If the seats are not tied into the frame, or to a cage, there is the possibility of them ripping out. I have seen tons of cages, both in 4WD's and stock cars, where the frame goes under the seats and the seats are bolted to them. What happens in this instance is the rest of the car (or jeep) can disintegrate around the cage, so the only thing left is the cage with me sitting on the seat. I'm probably getting a little paranoid here, and by the time I'm done it'll be a tank (like it isn't now). Did I clear anything up or make it muddier?

JEEPN
'81 CJ-8 Scrambled!
GM151/SM465/NP205 twinstick/7" Lift/33" Swampers/REP 8000/RS9000's/Scout II D44's F&R w/4.10's & Lockrights

 

I am not a crash expert by no means . This Jeep ( it was said) rolled over a quarter of a mile . If not for that nasty bend in the center of the hoop the roll bar for the most part stayed upright . I think what happened was the center hoop banged severily on a rock and then it looks like the sides started to close in . The write up says he was thrown from the vehicle , when ? That is probably what killed him . If I was going to be in places like he was I would not even think of going there without at least a 4 point harness etc.. I have seen my share of hwy fatalities and I have seen worse looking wrecks where people have lived . Some with minor injuries .Just for the fact they stayed in the passenger compartment . I cant say this here just for the fact of that center hoop closing in the way it did . If this guy was wearing a seat belt , why did he get tossed from the Jeep ? The seats are still intact ? Just trying to deal with the pictures like everyone else I guess.

Jeff

Happy Owner of a 1979 CJ5
Almost finished /wwwthreads_images/icons/tongue.gif ( Ya Right ! )

There`s No Such Thing As Surface Rust

 

People containment is the key. My best friend was killed in an accident wherein an 18 wheeler hit the minivan he was in. He was sleeping on the back bench at he time, while his baby brother and older sister were sitting in the second bench. Both he and his sister were thrown across the highway. However, even though the entire van collapsed around them, his brother and parents survived. They were contained inside the vehicle by their seats and seatbelts. The vehicle took all of the force, and the three survivors walked away with comparitively minor injuries.

A rollbar is one thing that I will not be holding offmuch longer.

Ed

**********
Just
Expect
Every
Problem

 

I totally agree with you Mark. I have my seat mounts tied into the cage (part of the cage really) and the cage tied into the frame at multiple points. If that cage does separate somehow, I want to go with it! It still amazes me that this guy obviously spent some serious $$$ and thought on his CJ, but had nothing other than the stock rollbar.

'75 CJ5,258,T18a,4.27's,33's,On-board air,Warn 8274

 

After CJ Dave posted about the death, I decided to go look...
I don't normally look at accident pictures, but sense CJ Dave said he couldn't get it out of his mind...

Looks like the center of the bar (not braced) got pushed down, and the subsequent roll overs caved the sides in.
Cause of death was probably head trauma.

No cage around driver, no cross bracing, no forward braces of any kind, no head protection (top bar forward) for either passenger.
That 'passenger protection' is a disgrace.
He spent all that money on upgrades for the Jeep, and couldn't 'afford' the one thing that could save his life in this situation....
Makes you wonder, doesn't it...?....

Spring over axle gave the suspension plenty of spring, and raised the center of gravity, making possible more rolls, and faster acceleration from the ground when it landed wheels first...
Spinning wheels, steep, off camber incline and solid obstacles (rocks) averaging 1 foot to 1-1/2 feet in diameter...
As soon as he hit a rock on the high side, it loaded the suspension on the high side, then the wheel popped over the obstacle, and the suspension unloaded...
Throwing the right front corner up in the air, and transferring the weight over the center of gravity to the low side (shifting the datum point), and breaking traction, and the roll began down the hill rear wards and to the left....
The ground digs in the pictures from the accident site show rock size, and the apparent route of travel...

It's a tragic loss, and completely unnecessary...

"I Have The Body Of A God... Buddha"

 

/wwwthreads_images/icons/tongue.gif I think that all things considered, having the Jeep intact would be better. it's like someone pointed out, more debris following downhill could injure you even worse. How would you like to be sitting in a detached tub belted in and woozy and look uphill to see the chassis get loose and slide down toward you. What you have to do is visualize your Jeep with only the rollbar "system" and nothing else......like an x-ray view. See what kind of structure it really makes, and how the joints connect. The frame actually IS the bottom of the "Box Section" that forms the rollbar "system", so it needs to stay connected. The white CJ WAS in an extreme roll, but I did once have a modified race car barrel roll eight times on an asphalt track, and the driver; though he lost conscienceness; was unhurt. In that case, the cage deformed somewhat, but the driver's compartment was still big enough for complete safety. As TR pointed out, without a cage, head trauma is a likely possibility./wwwthreads_images/icons/tongue.gif The two frame-to-body mounts on each side of the CJ that are just behind the front wheel and just ahead of the rear wheel are the most critical when it comes to holding the Jeep together. Believe me, I KNOW how pesky and time consuming it is to rebuild them after they have rusted, but without those, the tub may come off the frame. The picture of the white Jeep; as I mentioned; just confirmed my worst fears about what might happen if I didn't repair and upgrade those spots./wwwthreads_images/icons/tongue.gif

CJDave
Quadra-Tracs modified While-U-Wait by the crack moonguy/wwwthreads_images/icons/wink.gif Quadra-Trac Team./wwwthreads_images/icons/tongue.gif/wwwthreads_images/icons/smile.gif

 

I think it is a great tragedy. The commentary on the website that posted it (did you get there from the post on the Land Use Genral bbs?) is that it was a shame that the *tundra* was ruined, no mention of the poor sob that died.

There is a letter writing campaign under way (about the focus of the article on the plants rather than the person) to that website, also posted on the same thread on the LandUse General page here. Join in!

 

I too find this a tragedy and the pictures very disturbing. I feel very sorry for this poor man and his family. Keeping with this thread though, I am inclined to point out that it would appear as if this man was not wearing his seatbelt (unless it was unbuckled prior to the pictures being taken). Not to say that the seatbelt would have saved his life, but it could not have hurt. I have seen people literally walk away from some amazing accidents due to their use of seatbelts/airbags, and I have seen too many people die from similar accidents after being tossed from their vehicle because they were not wearing their seatbelts. Please everyone buckle up even if it is only "a quick trip to the corner store".

Depewtee '78 CJ-5 (for sale)
'90 YJ

 

Both drag racers and NASCAR racers have gone with the new technoloy theory at keeping one inside the cage and having the heavy elements of the vehicle go elswhere is the safest.
When you hit the the wall and/or start tumbling, the newest strategy is that you want your body inside the cage and you want the heavy stuff to do thier inertia thing somewhere else away from you.
I looks to me like the guy would possably have survived had he been wearing his seat belt. I suspect he was thrown out on the first roll and crushed.

JAF
http://www.monsterslayer.com/jeep

 

I think one thing we are missing in this thread is the construction of the cage itself. I AGREE with all of the above that frame tie-ins are a must for any serious off-roading. Or even any jeep that has the potential to roll all at (even show/street jeeps). Back to my point. THE DESIGN OF THE CAGE IS THE MOST CRITICAL PART. If you don't reinforce the cage at the critical stress points it will fold up like an origami. Cross braces, spreaders or trusses, what ever you call them need to be included. Granted a full roll cage is better than the factory, but it still is not enough. I'm sure those familiar with race car building know about trusses. All the tubing makes triangles, not squares. In a crash, a square will get crushed and turn into a diamond, while the triangle remains intact. (see picture).

Also, please leave the welding to the pros. If you're not 100% comfortable with your welding capabilities, don't try, your a$$ depends on it. Last point, NEVER use chrome in stress critical parts (rollbars, frame parts). When the metal gets chromed, the metallurgy of the piece changes and tends to brittle the metal, making it more likely to fail.

My name is Ted, and I'm a Jeep-a-holic. /wwwthreads_images/icons/laugh.gif
[email]tzeiger@excite.com[/email]

 

My prayers and sympathy go to the family left behind… a tragedy like this is never easy to fathom.

What good can come from such a tragedy? There are several people on several forums that are re-thinking how they wheel, where they wheel, and why. It’s never been a past time that’s not without danger. I feel that’s one of the reasons we love to wheel, and be around those of our own kind. That does not mean that we love to take chances with our lives, or the lives of our loved ones…but…humm let me explain this another way.

Long ago, before dirt, my dad ran a trucking company in Valdez Alaska. There were two ways to get into town… Half-mile Glacier and up over the Sugarloafs. If you went up over the pass one of the trucks dual wheels was hanging over the edge of the roadbed… into thin air. My dad loved to take that road… for the challenge. But he forbade any of his drivers to ever take it.

One day I was in his office while he was talking to two truckers looking for a job. The two truckers were arguing about how far they could get their bogies hanin’ over the roadbed on the pass. They’d each been over the pass many times before with a Semi… and now they were trying to best each others driving prowess. Then one looked at the other a bit disgusted and then at my dad and said: “Hell, Van! Give him the damn job, he’s nuts… I’m staying as far from the rim as I can! I don’t need this job that bad!” Well you can guess who got the job.

Only a few days later my father and mother, and myself, were up on the pass looking down at Half-Mile Glacier only to see a bridge collapsing under an Alaskan Freightways Semi. As the tractor and trailer slipped into the river my dad turned to mom and said: “See, I told you this was the safest way!” My mom never questioned him again.

Our lives are filled with if's and somedays… someday I’ll build that cage if I can figure out the design, someday I’ll install the 5 point harness if I can find one.

Often the someday never comes, but the need for it does.

I’ve learned a lot of roll-bar talk and fabrication here… but one thing I have not heard is about the tie down for the seats. Does it make sense for the seats to be tied to the roll bar mounts? If you’ve got to go on a roller coaster ride… make sure your seat stays firmly attached. That's lession I learned in the bush an early age from One-Eye'd Pete.. the local Bush Pilot.... maybe now it makes even more sense.

Good Jeepin'

Larry

 

One more thing.
If you are not going to build a cage in your jeep and you decide to rely on the bolts that hold the body to the frame, then you need to get some bolts that not only have high tensile strength, but they also have to have a high shear strength.
What I mean by this is the bolt can resist pulling apart lengthwise, but it also should be strong so that it does not break sideways.
This is a likely possibility if the jeep rolls and it lands on its side.
When it lands on the side, a great amount of sideways pressure is put on those four bolts holding the body to the frame.
Refer to the pic to see what I mean if my words have failed me.

"I see." the blind man said to the deaf woman./wwwthreads_images/icons/wink.gif

 

So Redbeard

What grade/type bolt fits into this catagorey ? Grade 8 / aircraft etc ???

Jeff

Happy Owner of a 1979 CJ5
Almost finished /wwwthreads_images/icons/tongue.gif ( Ya Right ! )

There`s No Such Thing As Surface Rust

 

/wwwthreads_images/icons/crazy.gif It's 1/2" grade 8 N.F. for us, Jeff. We have converted the four most critical spots on the CJ "system" to Gr. 8 N.F. for the VERY reason that was discussed. AND NOT ONLY THAT.....we have substituted square, close-fitted plates for the usual washers that fit unside the channel-formed frame mounts, so the bolts have something more substantial to pull on. The rubber mounts are actually for "isolation" only, and ARE NOT a structural part of the "system"./wwwthreads_images/icons/tongue.gif

CJDave
Quadra-Tracs modified While-U-Wait by the crack moonguy/wwwthreads_images/icons/wink.gif Quadra-Trac Team./wwwthreads_images/icons/tongue.gif/wwwthreads_images/icons/smile.gif

 

Jeepzilla posed an interesting question.
I have been under the impression that it would be better to use Grade 5 instead of Grade 8 bolts for the frame to body with the thought that the harder bolt will snap whereas the Grade 5 bolt will bend and be less likely to shear.
The same concept keeps turning in my mind as to bumper bolts, especially in the rear with a reciever. While I am using Grade 8's and squeeze tubes on my frame to 'L' braces, would it be better to use Grade 5's on the bumper/crossmember/frame braket connection? My (skewed?) thinking here is similar in that if a towed object got wild, the Grade 5's would be more likely to bend and hold rather than shear.
I'm not to keen on bolt theory so anyone who's in the know would be doing me a favor in enlightening this related subject.
TIA

JAF
http://www.monsterslayer.com/jeep

 

/wwwthreads_images/icons/tongue.gif The same thing entered my mnd, Jaffer, when I first thought about doing the frame-mount upgrade, but I was reluctant to use a 3/8" Gr. 8 because it may not be ductile enough. When I upgraded to 1/2" bolts I felt that I had sufficient diameter that NOTHING would bend or shear....period....especially since a rubber bushing was part of the connection.....that using Gr. 8 would be the right thing to do./wwwthreads_images/icons/crazy.gif

CJDave
Quadra-Tracs modified While-U-Wait by the crack moonguy/wwwthreads_images/icons/wink.gif Quadra-Trac Team./wwwthreads_images/icons/tongue.gif/wwwthreads_images/icons/smile.gif

 

Dave

Sure would be nice to have a peek at the way you have re-done your tub mounts. I am trying to visualize them but...
My tub is off the frame and I am re-working the whole thing and have stared at them too trying to figure out something better. Now is the time for me to do this upgrade when the tub is upside down . Thanks

Jeff

Happy Owner of a 1979 CJ5
Almost finished /wwwthreads_images/icons/tongue.gif ( Ya Right ! )

There`s No Such Thing As Surface Rust

 

Yea JEEPN I see what you mean but by the same token you would have to completely mount your seat belts to the roll cage so if seperation did occure you would not be beheaded by your seat belts.

 

Jeepzilla, I am not going to lie to you.
I am not an expert on the different strengths and weaknesses of bolts.
I haven't got to those classes yet.
I was just thinking, and it seemed like a very important issue to mention.
I figured Dave, Jaffer, and others had already thought about it, but I wanted to bring it to the attention of those who had not thought about it.

Personally, I think it all depends on the diameter, and material of the bolt that matters.
Just my un-expert opinion.

"I see." the blind man said to the deaf woman./wwwthreads_images/icons/wink.gif

 

No matter how high tech you wanna get, a full cage welded by a competent welder and attached in a secure fashion is going to be a lifesaver. The incident with the guy killed last week really started a lot of us thinking about safety and cages in particular, yours truly included. Unfortunately, if you are not going to do a cage yourself there are folks out there that do decent work but charge beyond real prices, especially around here. A guy in our club paid 1200 bucks for his cage, nice work, but nothing special. There is another guy in our club that I was talking to about this cost situation a couple months ago, he works at a big 4by and truck accessory store. He too was angry with the ripoffs going on for pretty straightforward work, so decided to do something about it. This place is now capable of doing a nice cage using the stock rollbar as a basis for about 300 dollars or so. I'm having mine done, front hoops, spreaders, back bars converted to YJ style hoops for passenger protection. the reason they are doing this for that kind of price, they want to see more people wheeling reponsibly and safely, especially the younger ones that have seen reock crawling on TV or something and think they can just go out and do it. My whole point with all this is safety should be first, but simple can be good, jsut as long as it is sturdy.

Brad
ORC Land Use Section Editor
http://www.off-road.com/land