Roll cages, your views

[Chucaro]

We all know that if the Land Rover has one weakness is the body structure and protection for the passengers in case of a serious accident which are common in expeditions of the outback
I think that it would be interesting and for the benefit of all of us who drive a Land Rover vehicle regardless of the model, sharing our views regarding the need, effectiveness and type/design of roll cages that we prefer to fit in our vehicles. It can be based on our previous experiences or in the unfortunate experience of others.
Those who have been witness of vehicles involved in accidents can share with us their views of the need and effectiveness of the roll cage fitted in the vehicle in question.
There are two types of roll cages that come to my mind, the ones fitted inside of the cabin and the external cages which in many cases is incorporated in the roof rack.
In both cases we can review the ones with the components welded and the others which have the components assembled together by fasteners (bolts, nuts and roll pins)
The beautiful rig of Graham Jackson comes to my mind as an example of an external protection for the Defender.
An example of an internal roll cage can be seen in http://www.safetydevices.com/index.php?option=com_content&task=view&id=64&Itemid=64

Your inputs will be appreciated

Cheers

 

[stevenmd]

Roll cages add weight, there is no doubt about that fact. But, IMHO, they should be a must when it comes to safety on expeditions. I would never take my family on a long range expedition without one.

External versus internal: external cages usually are not pleasing to the eye and conjure up thoughts of rock crawlers. Internal cages can usually utilize 6 or 8 point webs, therefore, in my opinion, are stronger.

I'm not sure Safety Devices is still in business. Your best bet, if you want one, is to have one custom made by a local fabricator that the jeep guys use.

 

[Chucaro]

Yes, I am going to make it, I made the questions to research about wich is the best way to go.
I guess that this thread can be for the benefit of all of us if many members come with ideas and inputs.
Cheers

 

[TeriAnn]

Your inputs will be appreciated

Golly, I'm back and fourth on them. If I could have one without adding weight and raising the roll centre I'd do it in a heartbeat.

But in a way roll cages can be a self fulfilling prophecy. They add a lot of weight up high on the vehicle causing to to roll over at less of an angle. But you have more protection and less damage (with an external cage) when you do fall over. I'd love to have an external roll cage, but I'd rather have a lighter weight vehicle with a lower centre of gravity.

For an expedition rig I think a lighter weight vehicle with low centre of gravity and good driving skills beat having a roll bar. For a rock buggy or a vehicle storming steep mountain sides I'd opt for the roll bar and just assume I'd roll down a hillside every once & a while.

Interestingly enough most vehicles I have seen fall over have a roll cage and heavily loaded roof rack.

 

[Chucaro]

In some ways I tend to agree with you regarding the stability issue and for that reason I have more inclination for the interior roll cage/cargo barrier than the external armour with the roof rack.
I do not believe that an internal roll bar will affect much the stability angle of the vehicle providing that the mayority of the heavy cargo (water & fuel) are located under the seats level.
This image from the web of which are many familiar will show my concerns.

Cheers

 

[overlander]

Here is a picture of an NAS 110 (not mine)that lost control and rolled onto it's side while driving down a road. It was righted and repaired by my specialist.

I'm a fan of the cage, and I like that my rack won't wear out my rain gutters.

 

[ntsqd]

This topic seems to spark controversy over just about any aspect of design and fabrication of a cage.

I see roll cages as a huge bundle of compromises. A couple:
Tube Bend radius: Larger is stronger and more in the way of other stuff.
Cage legs anchors: Better to tie to the frame, but then the body pays a price unless all are unitized, and that's a can of worms by itself.
Strength thru design (rather than mass): Proper triangulation & continuous load paths interfere with the actual use of the vehicle.
Seat mounts vs. seat belt mounts vs internal cage: Ideally all 3 are one unit. Do not want any moving independant of the others.

I see no good answer for the first issue. Each bend will have to be eval'd for best compromise bend radius (assuming there are options).

I can offer a design idea to help with the cage legs, but it is a *lot* more work (both design and fab) than simply bolting in a cage via load plates.

Triangulation is a toughie. Simple in concept, not always so simple to execute.

 

[MoGas]

Do Defenders have removable tops? What are they made of? I'm of the opinion that a removable top vehicle should have roll protection made from a minimum 2 inch OD x 0.120 thickness 0126 DOM steel or 1.625 x 0.102 4130. Of course, if using an alloy such as SAE 4125 or 4130 you must normalize the cage after welding or it will be brittle. Not many people have access to an oven that can do this.

If you are building a full internal cage, Roll cages can use smaller tubes since a cage is a stronger structure. On a removable top vehicle for a cage I'd start with a minimum of 1.5 x 0.120 1026 DOM or 1.5 x 0.095 4130.

For NON removable top vehicles, you have a few considerations. You pretty much have to stick with DOM steel because you will find it difficult to normalize the alloy steels in the vehicle. On my Land Cruiser, I have designed a cage of 1.5 x 0.120 1026 DOM that will require me to remove the dash and weld the front bars and a bolster bar across the firewall from one side to another. Then I will reinstall the dash pad after modification so as to avoid Z bends like these:

I'll also be using a mandrel bender for mine. I'll probably finish the passenger area similar to this:

I'm not claiming to be an expert, I just want to be safe. I did, however, stay at a Holiday Inn Express.

Dave

 

[Connie]

I have seen too many pictures of rolled trucks without roll cages so my opinion is for it. First of all it makes the difference between a rolled vehicle (with much swearing) and scrap metal (with much crying). I would advocate for the external roll cage so that space is not lost on the interior. I love my roof top tent with down duvet and full sized pillows, and having it mounted on the roll cage relieves the pressure from the roof. I also have dreams of owning a hamock and being able to tie it between the roll cage and the one suitable tree in the desert, campground, backyard whatever.

That being said, I also agree that it makes the vehicle somewhat less stable, and the temptation to overload a roof rack is hard to resist.

Hey that means all of those rocks I pick up along the way aren't overloading the truck, they are simply balast and I am mearly thinking of our safety and the stability of the truck , right??

 

[Chucaro]

Going for some Discovery images that are in the web and wrecked vehicles here in Oz, looks like that the Disco is as bit better than the Defender in how surviving a roll over, but just only behind the front seats. I am looking for a way to make an external cage on my Disco without upsetting to much the looking of it but it is difficult without making holes in the body.
Seems to me that an interior roll cage is the only answer in the Disco.

 

[Harald Hansen]

I test drove a few Defenders before buying the Disco 2, and budgeted for a roll cage if I were to buy a Defender or Disco 1. It seems to me that the occupants in a Discovery 2 is very well protected in case of a roll, so I'm not sure if I want to fit a cage.

Protection and Performance in the UK have this nice-looking number for the Disco 2, though:

If I ever get one, I will have them put in brackets for a roof rack.

 

[Spikepretorius]

I think a rollcage on a Landy is an essential. Not necessarily the Disco's but the Defenders and earlier models definitely.

I know the driver of the crashed Landy in the pic posted here. Well his wife was driving actually. (He now drives a Cruiser)

Even ask Aubrey, who's also a member here. He's had clsoe shaves and about a year ago or so he wrote off one of his Landy's just drivng home from the office.

Regarding the bolt-together internal cages, they work fine. I had one like that in my race car and it passed all the requirements. The downfall there is building it neatly to tuck out the way. It's a kneecap magnet.

 

[Dances with trees]

I did a rebuild on a 110 that rolled, they had too much on the roof rack, got the death wobble and that was that. Put her on the side and skidded down the highway for a hundred yards or so. Roll cage saved then and the truck from a total loss.
The North American Cage is tied to the frame the external part bolts to an internal which in turn... you get the idea.
I have a safety devices cage on my 90, unfortunately they seem to go in and out of business as ofter as the full moon arrives. No idea if they are back at it or not.
If you decide to build your own, remember triangulation is your friend...

kevin

 

[Hunter]

This is a good thread and thought I would add my .02 to the thread. I admit, I am not an expert on Rover's. So I dont know the exacts of the vehicle line. But I have built roll cages for many, many different 4x4's in my 10 years as a professional fabricator. Some good points were brought up, but there are some myths.

The most common I hear is "weight". "It will alter my center of mass". For practical purposes,this more or less false. Here are some rough averages for a SUV type roll cage for the interior.

80 feet of tube at 1.75x.120 wall tube, 1.8 lbs a foot = 144 pounds.
Add in some plates, hardware, some misc tube work and mounts, call it 175 pounds that is spread out over the entire vehicle. It will not affect your balance or center of gravity. And this is on the heavy side of the questimate.

1.75 thick tube is kinda on the heavy duty side. You could build one out 1.5x.120 wall material, built well, (tight, easy gradual bends), it will take a pounding. I have had a few tested, so this is coming from real world observation. You could pick up some room inside and knock off 20-30 pounds.

Then, there is the outside, inside debate. No doubt the exterior cages are heavier as they require quite a bit more material. Maybe closer to 250, but again, it spread around the entire vehicle. Might notice it more, but it shouldn't affect your sense of balance. An interior cage should be treated as a one time insurance policy... cause chances are if you roll the 4x4, you will have pretty wicked damage to sheet metal and the windshield frame..which is a bugger to fix. But, you walk away and hopefully, structural damage is limited.

And Exo, can be handy. While bulky and a bit heavier, you can use them a few times. Built right, the are fantastic in protecting from the bumps and grinds of canyon walls, ledges, trees and yahoos in the parking lots. And if you roll, can cut done the damage considerable to the outside of the 4x4. Most cases, a cage can be rebuilt cheaper than repairing the body, door and windsheild frame.

 

[ntsqd]

FWIW I see no value in considering 4130 ("chro-moly") tube. 4130 was designed to be welded using Oxy-fuel to build engine mounts for aircraft during WWII. W/o proper heat treatment of TIG or MIG welds the tube will be far stronger than the welds. Keep in mind, on any fab project, that welds are an "On-Site casting". Nothing better, nothing less. The welds, as done with any method other than an Oxy-Fuel torch, will be brittle until properly Normalized. The reason for this is that the metal only 1/4" away from the weld puddle is an iceberg in comparison. It will rapidly cool the weld metal resulting in freezing it in a disadvantageous (brittle) crystalline form.

The reason race cars use it is to reduce weight. They can get the same strength out of thinner walled tube. At considerably more expense.