Roll cages, your views

[BigAl]

An interior cage should be treated as a one time insurance policy...

I would add that cages aren't just for rockcrawlers, I've been in 2 rollovers offroad, neither were expected. It is very reassuring to be well belted and surrounded by tube when you are in a precarious spot.

This isn't the vehicle type in question but this style internal is very livable.
I would do the bar behind the seat different for a vehicle with a back seat but otherwise I don't think the internal cage hinders much. It also provide secure mounting for other accessoris like cargo trays, cb or hilift jacks.

 

[pangaea]

Not that I'm covering new ground here, but my 2¢ for whatever its worth is that a roll cage is a VERY nice thing to have on expedition.

First off, the safety factor is hard to argue. While a roll cage can minimize the damage to the vehicle, it also minimizes the damage to the passengers inside. I wouldn't relish the idea of having to deal with a major medical catastrophe from a roll over 100 miles from civilization.

In the Central America forum we were talking about bad roads. There's a notoriously bad road from the Belize border up to Tikal in Guatemala. A few years ago, a bunch of us were driving that bad road around dusk. The road is notoriously unsafe after dark, so we were racing the sun to our destination. The lead vehicle rounded a corner and there was a pig in the middle of the road. I was second in line and dodged the pig, but the lead truck hit that pig and did a baja jump. Had he not hit the pig square on, we could have been royally screwed to say the least.

The second big advantage of a roll cage to me, is the fact that it ties the roof rack into the frame, instead of putting the stress of the rack and its contents on the fragile rain gutters.

The caveat of course is that a roll cage does add extra weight to the top of the vehicle, increasing its center of gravity. As long as one realizes that, and adjusts their driving habits accordingly, and provided one doesn't treat a frame attached roof rack as a license to overload the rack, then I think the benefits of a roof rack FAR outweigh the drawbacks.

 

[MoGas]

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.

I only brought up alloy steels (4130) because it is an option. I weld it at work (along with stainless, aluminum and other metals) and we have the facilities to normalize a decent size peice. Most people probably don't.

 

[kjp1969]

Remember your melon.

Remember that an internal roll cage introduces a whole bunch of hard metal into the interior and it all should be well padded. Most of the interior of modern cars and trucks has softer plastic and fabric in likely impact areas. Even with padding, if you hit your head on a roll bar, you're going to be hurt. Race car drivers wear helmets to protect their head from hitting the roll bars, and not much else. A lot of the pictures I'm seeing have unpadded metal right above headrests- not a great idea.

Most of us think about "soft" rollovers at trail speeds, but you're probably also driving on higher speed highways. I'd vote external cage- keep that metal away from your melon.

 

[Alaska Mike]

I'm kinda conflicted on this one. Most "roll cages" I see on Land Rovers are more for show. They look impressive at a glance, but a closer look shows that they aren't tied together in any real structural way, except at the top. No frame tie-ins, just mostly bolted onto sheet metal, and not always in the best places for strength. In some cases I can see them being more of a liability.

Interior roll cages that are more of a structure within the vehicle provide a greater degree of safety while maintaining the overall appearance, but sacrifice interior space. Some vehicles can handle this more than others. As mentioned, they do nothing for the body.

Exterior cages that are tied into the frame or otherwise braced in a way to provide support for all of the "legs" are my preferred method. There are certain drawbacks, but the advantages outweigh the drawbacks in my opinion. They provide a roof rack mounting point and sheetmetal protection, deflect branches and other off-road hazards, take up little or no interior space (depending on how they are braced), and just plain look cool.

However, none of this is cheap, and there are a lot of things on my Rover that are greater safety concerns (like seatbelts) than a roll cage. Once those are dealt with (and the myriad other things), I'll look at designing a cage with the best features I see in other cages.

 

[ntsqd]

I only brought up alloy steels (4130) because it is an option. I weld it at work (along with stainless, aluminum and other metals) and we have the facilities to normalize a decent size peice. Most people probably don't.

I think bringing it up was a good idea. A discussion such as this should include it, and it's pitfalls.

 

[ChuckB]

Here's an example that I found on the net somewhere of an FJ55 with an external cage. Not sure who owns this vehicle, and it's not a great picture. But it looks like the cage is tied into the body just below the windows.

 

[Chucaro]

The Design in the Toyota is similar to the one in replay # 11. I would like to know if in the design for the Discovery is another piece of pipe inside of the vehicle as a continuation of the outside structure. If not, I cannot see how effective this design is.
Regarding the weight distribution I agree with the point that all the weight is spreaded evenly so it is not much of a problem. Also if we load weight in a roof rack which is supported by the external full cage the weight will be transfered to the chassis. This is more effective than supporting the rack on the gutter.

 

[revor]

We did ours all internal http://www.washbrook.net/Stage 5.htm The car is in Melborne if you are close enough to have a look. It copies a Safety Devices in the lines but for competition it had to meet the conditions of the Australian Racign guys.

 

[ntsqd]

A footnote on load spreading plates, I've run across the idea that they should not be the same size & shape. The idea being that if they are differently shaped or of different dimensions that they can't act in concert to shear through whatever sheet metal the cage is bolted to.

 

[Chucaro]

Thanks Keith, I am about 3000 km north of Melbourne, but if I have the time during my trip next March to Tasmania I will have a look.
This is a very interesting thread and the response here by the adventures community it is different to the response in AURLO.
Cheers

 

[bfoxg8r]

I've seen these in person, and they are very nice.

http://www.stableenergies.com/products.asp?dept=173

 

[revor]

Ah read close it's a Safety Devices cage.. Nice stuff but made from "unobtainium" I have perhaps one of the last RD109 (Euro exo/internal Camel style) SD cages uninstalled in the world. I got lucky and just sort of happened onto the pieces needed. I'm very confident it will work great in the event of a rollover but I would prefer to build my own, not that I have the time to install the one I have. For something like a Defender that has limited acrual structure built into the design of the body I will not hesitate to do a cage. In something like a Disco I don't worry as much. I have seen Disco 1's after a roll on the interstate at interstate speeds and knew the passengers walked away. The Disco's have mighty strong body work, as does an 80 series Toy. They are designed to absorb energy and look a mess after a rollover or other major collision. I "play" with my D1 in situations that some might think a cage is a must but haveing cut these cars apart numerous times I'd say you're in good shape off road without on unless you plan on more than some 50 MPH.. I will be putting a cage in my D1 in the next year but only because I'll be cutting the back off and making a a trayback (no body structure left). Oh... And that over 50mph thing? We'll have to see.

 

[Green96D1]

Ah read close it's a Safety Devices cage.. Nice stuff but made from "unobtainium" I have perhaps one of the last RD109 (Euro exo/internal Camel style) SD cages uninstalled in the world. I got lucky and just sort of happened onto the pieces needed. I'm very confident it will work great in the event of a rollover but I would prefer to build my own, not that I have the time to install the one I have. For something like a Defender that has limited acrual structure built into the design of the body I will not hesitate to do a cage. In something like a Disco I don't worry as much. I have seen Disco 1's after a roll on the interstate at interstate speeds and knew the passengers walked away. The Disco's have mighty strong body work, as does an 80 series Toy. They are designed to absorb energy and look a mess after a rollover or other major collision. I "play" with my D1 in situations that some might think a cage is a must but haveing cut these cars apart numerous times I'd say you're in good shape off road without on unless you plan on more than some 50 MPH.. I will be putting a cage in my D1 in the next year but only because I'll be cutting the back off and making a a trayback (no body structure left). Oh... And that over 50mph thing? We'll have to see.

I agree with Keith.

The D1's do protect occupants very well. I also saw a D1 rollover 3 times on interstate 80 while going to Reno. the truck did look bad however all the doors did open and all four Adults walked out without any bruises or any that were visible.

now a Defender which is a bolt together vehicle lacks the ridigity of the upper body like a Disco and therefore thats why all Defenders imported to the USA had to have internal Roll Cages.

will I ever get a Roll cage. maybe if my D1 ever becomes a serious rockcrawler trail rig. but until that time I feel pretty safe in the Disco as is.

 

[Chucaro]

Chances are that I am going to keep my Disco because I am not prepared to sell it for about U$A 9000. It is to good car to let it go. I just may get an old Rangie or County to do the tracks at the mountains and other severe 4wd trips.
With that in mind perhaps the right approach with the Disco will be move the cargo barrier forward, just behind the front seats and incorporate a roll bar around it together with the frame of the storage system.That would be very strong.
This approach is easy for me because we do not need the rear seats and will finish with a good cargo capacity in the vehicle.
The only problem with this design is that I am not reinforcing the weak point that is above the windscreen.
Life is full of compromises