internal (rear) roll cage

[Nay]

I want to add one more point here - even a well designed 6 point cage is quite obstrusive, especially once you add the protection foam. I did so many things to my old XJ, including an 8" lift, and at the end of the day the roll cage was what finally pushed it over the edge. I mean, I am sitting here with a wife and little kids and a supposedly dual purpose rig with a six point cage and getting ready to install offroad seats with five point harnesses.

I am 6'3" and I don't worry about offroad rolls because they are slow speed - I am not aware of any "SUV" that handles a roll on the a-pillars terribly well, but you never hear of that killing or severely maiming people in a single drop on the roof type roll. It is the multiple high speed onroad roll that is scary. Damn straight I'd want everybody in a five point harness with a full cage, but then every time you go to the grocery store you are in a roll rage with a five point harness.

If anything, I'd do B and C pillar hoops with triangulation bracing to the rear (not fun for second seat entry, but tough luck). Once you bring all that stuff up in front of the driver you are living with it every second you are in the rig and about six months from making a sale.

Nay

 

[LandCruiserPhil]

I want to add one more point here - even a well designed 6 point cage is quite obstrusive, especially once you add the protection foam. <snip>
Nay

Not true in my case I do not find it my way at all.

 

[fzj80kidpen]

All that weight up high just makes you more likely to roll.
Pick you poison carefully.

 

[peepers]

some more pics if interested

 

[PHAEDRUS]

Well as far as I know I am one of only a handlful who have ever flopped and 80. Wrenchs was worse tahn mine if memorey serves and I beleive Dan Kliers has the worst one yet. Both mine ad Wrench's were low speed off road, Dans was at highway speed while towing.
I was able to stare at my truck after a low speed roll and Dan's truck for a long time after a high speed roll. Quite frankly was very pleased with the performance on both vehicles as far as structural compromise. The A pillar is definitely the weakest point of the structure, followed by the c-pillar toe 1/4 window area. This is ind of common sense as they are teh longest expanses with the least amount of steel and reinforcement.
I know that Mark Hawley at metal tech was working on a internall roll cage for the 80 series but I can not for the life of me figure out a way to tie to the floor on the a pillar on the inside of the vehicle wtihout making bends around the dash. I know Wrenches cage has these bends and while they IMHO will work quite well in an off road situation in protecting the occupants.

The issue comes up on the way to the trail. Those s bends IF they fail will collapse and push back into the passenger compartment. This is exactly against all accepted automotive theory and design. I look at wrecked cars all day every day and not to toot my own horn but have a pretty good understanding of physical forces at play in an accident be it rollover or simple impact. I dont think the internal cage is a great idea. perhaps Dan's concept of b and c pillar hoopps makes the most sense as there is little to fail and be forced in towards the occupants. Granted there is not a pillar protection in this design but there is less risk to go along with components failing and coming into the passenger compartment.

Sorry for the rant, I guess I am trying to say, a roll cage is great in a dedicated off road rig, it is a compromise in a daily driver. IMHO an exo cage, ala action jackson is the most passenger safe way to protect in a dual purpose rig.
Dave

 

[IBCRUSN]

Chris (Wrench) post up some shots of your cage. I have seen his in person and looked more than adequate for your average slow speed roll. I guess rolling once crushing the A pillars will do that.

 

[SUMOTOY]

...
The issue comes up on the way to the trail. Those s bends IF they fail will collapse and push back into the passenger compartment. This is exactly against all accepted automotive theory and design. I look at wrecked cars all day every day and not to toot my own horn but have a pretty good understanding of physical forces at play in an accident be it rollover or simple impact. I dont think the internal cage is a great idea. perhaps Dan's concept of b and c pillar hoopps makes the most sense as there is little to fail and be forced in towards the occupants. Granted there is not a pillar protection in this design but there is less risk to go along with components failing and coming into the passenger compartment.

Sorry for the rant, I guess I am trying to say, a roll cage is great in a dedicated off road rig, it is a compromise in a daily driver. IMHO an exo cage, ala action jackson is the most passenger safe way to protect in a dual purpose rig.
Dave

Dave:
I'm not sure I agree with this at all. A bend 'can' be the weakest link to a cage, it's not innate. That really has to do with the location of the impact itself. There are several S bend cages I've seen over the years that woyuld pass a variety of tech rules. In a race cage, you just aren't going to see that many of them, but that's a convenience issue (no interior) more than structure. Assuming the cage is mandrel bent of the proper diam and thickness, an S bend isn't inherently 'less safe' than any other type of bend. Triangulated, it can be stronger.

If you have a concern over a cage S bend in the dash area, you can triangulate to the A pillar, which massively increases the deform rating of the cage itself. This type of trianglulation is required in highest rollover potential production based race cars, ala ProRally...

I'm not sure how any proper thickness/material cage will be inherently 'less' safe than no cage. That doesn't make sense to me. As a rule, and tech inspector for many marque events, I give a lot of latitude to straight triangulation cages, since it's not a race car. If it has the 'elements' of race car design, some creativity in allowing for a functional dash street car is dictated. Why? Because my philosophy as a Safety Steward is to encourage dual use cages, not discourage them.

What appears to be flawed in your argument IMO, is that an S bend might deform and cause occupant harm. I look at that scenario a lot differently. If the A pillar is crushing, isn't the risk to the occupant already magnitudes higher than without any cage? So much so that if the S bend is deforming enough to cause injury to the occupant, there most likely wouldn't be much of an occupant otherwise?

I am quite involved right now with the cage safety issue in primarily street cars, and have been in competition for many years in a variety of rules. I don't agree with the pysics or intrinsic argument you present. My primary concern in a non -sanctioned dual use cage is identification and restricting the definition of 'show cage' vs 'safety cage'. In that context, a rule variance to an S bend or modification to allow street/full interior use is a lot easier to grant, than a variance to material/thickness and *basic* triangulation rules.

An exo-cage has more inherent danger associated with passenger safety than an internal cage. Internal cages rarely get caught and torn by the hazards encountered during the roll.

My .02 arbitrage thru the peso

ST

 

[Wrench]

Chris (Wrench) post up some shots of your cage. I have seen his in person and looked more than adequate for your average slow speed roll. I guess rolling once crushing the A pillars will do that.

Ok but I got flamed before because several people said it was a poor design. Round 2. Here we go! Flame away!

 

[landtank]

From the pics that I've seen of rolled 80s I don't see a need for a cage. Has anyone not walked away from a roll in one of these trucks?

 

[Wrench]

I didn't walk away from mine..I ran!! I thought it was gonna blow up like they do in movies. LOL

Anyway you bring up a good point.As I believe Gov regulations require the roof of a vehicle be able to support the full weight in a roll over. But in my roll the A-pillars crushed halfway down almost hitting my head. That was just one roll. If it went over again it would of been much worse. So a cage is just added security. I don't want to be forced to be a midget.

 

[scottryana]

I think Wrench is exactly right. The fear isn't in a single slow roll, but multiple rolls. If you wheel any where were you have the chance to slide off the road or trail and take multiple rolls, and you have your family with you a cage is almost a must.

Ryan.

 

[landtank]

Lucky for me I have my seat moved back and my head is out of the way hopefully. With my size an internal cage would just beat the crap out of me on a daily basis.

 

[landtank]

I think Wrench is exactly right. The fear isn't in a single slow roll, but multiple rolls. If you wheel any where were you have the chance to slide off the road or trail and take multiple rolls, and you have your family with you a cage is almost a must.

Ryan.

If the trail gets that dangerous my passengers are walking, cage or no cage.

 

[IBCRUSN]

Chris,
Flamed or not your cage is far better than the rest of us with nothing. Sure, there are things that could make it better/stronger but is it necessary for your intended purpose? For the uneducated unless it is grossly overbuilt like a tube buggy or an USAC sprint car some people won't see it for what it was really intended, additional safety just in case. No one goes out to roll an 80 on purpose like you would a built 40 or a tube buggy. Just remember, when the next guy rolls his 80 back east, if he's still vertical that night he'll be drinking a beer and scoping out your rig.

 

[GXO]

Most of my theory on the non-full cage (box over passengers) was to simply reinforce the area that was already strong for DOT reasons...for the reasons mentioned here...multiple rolls, etc.

 

[IdahoDoug]

I've always liked the factory external cage on the Land Rover 110's that were sold in the US in the early 90s. Only a few thou were sold and they were all white with an external roll cage.

DougM

 

[SUMOTOY]

If the trail gets that dangerous my passengers are walking, cage or no cage.

I think in reality that rarely happens. I look to the one just recently that was an innocent backup onto a berm that rolled the truck. Isn't wheeling by definition, risking a roll?

I might modify your quote to read: If the trail gets that dangerous, every occupant should be wearing a helmet, cage or no cage. Rolls have the highest risk of head injury.

Using either quote, the fun factor of wheeling and the reality dictate neither ideal really happens.

ST

 

[LT]

So how much interest would there be if there was an aftermarket 80 series cage?

Just curious, because I might know of a place that has rough plans of one already

 

[GXO]

I would be if it was similar to my earlier post (with the drawing).

 

[landtank]

I look to the one just recently that was an innocent backup onto a berm that rolled the truck. Isn't wheeling by definition, risking a roll?

I remember that one and think it's another example of how well the truck performs in this situation. Once righted he drove it out. His logon was Nick something, I can't remember, but it would be good to review his pics while on topic.