Nigelw Posted November 20, 2014 Share Posted November 20, 2014 Had a good hunt around the net and I can't help but wonder which roll cage is better, internal or external? It was inspired by the tales of HfH and the Mille De Rivieres, where a RRC was written off and had to get the big yellow taxi home. I can't help but wonder which offers the best level of protection to my Discovery? And I don't just mean the ability to walk away from an otherwise serious roll, I mean more in terms of vehicle survival. Any roll-over experts care to enlighten me? Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted November 20, 2014 Share Posted November 20, 2014 Inner and outer, outer only means it's very difficult to do it to MSA spec. Quote Link to comment Share on other sites More sharing options...
Nigelw Posted November 20, 2014 Author Share Posted November 20, 2014 Bolt in inner cage FIA/MSA spec will hit me up for €1600 so doubling up will double the cost and add double the weight. Quote Link to comment Share on other sites More sharing options...
bishbosh Posted November 20, 2014 Share Posted November 20, 2014 Depends what you want protection for - if you "interact" with tress and undergrowth a lot then an external cage, or at least suitably positioned bits of cage to act as sliders will protect your bodywork. If you just want your head to be the same shape after an "incident" then fit an internal cage but be prepared to chop holes in the dash. Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted November 20, 2014 Share Posted November 20, 2014 Inner needs only to be hoop, cross brace, and rear stays, then you are safe. Join it through the roof to the outer part of the cage, which includes whatever you want then. I would suggest external windscreen hoop, roof rails, triangulation/cross in the roof and then think about what other body protection you want. I won't work out much heavier than a full internal or full external. Quote Link to comment Share on other sites More sharing options...
miketomcat Posted November 20, 2014 Share Posted November 20, 2014 I'm considering a cage on the ibex (at a much later date) my plan would be internal rear hoop and rear stays then external tubes from the hoop through the body along side the roof line and down the A pillar to the chassis then a tube across the top of the windscreen. This should be to msa spec (may require a tweek) and still protect the main contact points of the body. This would be more tricky on a disco but I think doable. Mike Quote Link to comment Share on other sites More sharing options...
Nigelw Posted November 20, 2014 Author Share Posted November 20, 2014 The Safety Devices 6 point bolt in has 3 internal hoops and goes down the inside of the screen A pillar, I am thinking that it would need to do the same on the outside at the screen and first front hoop. Bad feeling the extras I think I'd want will see this enter the realm of custom cage fabbing I can't actually find anything on the net for an off the shelf full external cage for a Disco Quote Link to comment Share on other sites More sharing options...
Cynic-al Posted November 20, 2014 Share Posted November 20, 2014 My RRC cage was made by p and p. They have loads of examples of work on the website. The problem I see with all external is you can't have a side to side diagonal. Ok you can put diagonals on the roof etc but when your looking from the back it's still a square with no bracing. Obviously if you've got 3 or 4 hoops it's going to take some bending but it still seems to be lacking something that can be added really easily if you have it internal. Why not have your hoops internal but the longitudinal bits on the outside to protect the corners of the body. If your competing in something that is going to see you constantly on your side against stuff wouldn't you be better ditching the body and have a cage with in fill panels? Then the body is the after thought made to fit rather than the structural cage? Quote Link to comment Share on other sites More sharing options...
elbekko Posted November 21, 2014 Share Posted November 21, 2014 Bolt the external cage to the internal cross brace behind the seats through the roof, you'll have strength + headroom then. Quote Link to comment Share on other sites More sharing options...
Dave W Posted November 21, 2014 Share Posted November 21, 2014 I think I'd go for an external cage (as I have done on my competition and overland vehicles) but, as others have said, link it to an internal hoop. The internal hoops on mine have bolt in bracing so we have the option, if needed, to remove the "cross" in the internal hoop when the extra space is needed. I used to compete (challenge events and trials) in a Range Rover and had an FIA spec internal cage to protect me and had an external aluminium cage made to go on the outside to protect the body from trees etc... and give some body protection in the event of a rollover. The aluminium cage wasn't expected to do much during a rollover but was there just for body protection and was pretty light, it worked really well against the trees. There's a pic of the cage here, not the prettiest thing but was very effective at keeping the trees off the bodywork, particularly with sill level tree bars added. Quote Link to comment Share on other sites More sharing options...
Chicken Drumstick Posted November 21, 2014 Share Posted November 21, 2014 Had a good hunt around the net and I can't help but wonder which roll cage is better, internal or external? It was inspired by the tales of HfH and the Mille De Rivieres, where a RRC was written off and had to get the big yellow taxi home. I can't help but wonder which offers the best level of protection to my Discovery? And I don't just mean the ability to walk away from an otherwise serious roll, I mean more in terms of vehicle survival. Any roll-over experts care to enlighten me? I think you really need to ask yourself what you want the cage for. e.g. Competition use? Off road use? On road use? An internal cage will keep the external dimensions of the vehicle stock, so it'll fit through the same gaps it always has. But to be honest, an internal cage can be more dangerous to occupants than not having one at all in an accident. Hitting yourself against the cage in an impact will not be good. So for an internal cage you need proper supportive seats and full harnesses. And this needs to be for every seat in the vehicle that you want to use. Internal cages will also take up room in the vehicle and possibly mean hacking up bits of the interior. An internal cage also won't offer any protection to light impacts, such as rubbing against trees or rocks. If you want to enter any competitions, you need to check the roll over cage regs, as many bolt in cages will not meet requirement. Quote Link to comment Share on other sites More sharing options...
Tanuki Posted November 21, 2014 Share Posted November 21, 2014 Think of 'liveability' - if you do a lot of road-mileage an outer cage can kick up a hellish amount of extra wind-whistle at speed (same goes for roof-racks). OTOH an inner cage means you lose some usable passenger/cargo-space. Some can also restrict usable seat-adjustment/positioning range. Also - depending on the attitude of the police/VOSA/range-wardens/gamekeepers/estate-managers/horseriders in your area the vastly lower visual impact of the internal cage could be an important factor. Quote Link to comment Share on other sites More sharing options...
Nigelw Posted November 23, 2014 Author Share Posted November 23, 2014 The live-ability issue of an external cage had not exactly entered my mind good point though! I want it to protect me and my investment, it is going to be in what will basically be my daily driver/off-roader/competition truck, this thing has to do everything, I don't want to run a second vehicle. Gonna call a couple of custom cage builders first and see what numbers they come up with for roughly what Im looking for, if I can get them to price it in a moduar way I can price it against the off the shelf internal with any of the extra modules added. Quote Link to comment Share on other sites More sharing options...
Maverik Posted November 24, 2014 Share Posted November 24, 2014 Nige, if you're bolting a cage to a discovery I'd seriously look at doing some re enforcing of your sill body mounts and possible your bulkhead mounts those cages are heavy and those wee body rubbers weren't designed for such a huge weight applied to them... ask me how I know this... Quote Link to comment Share on other sites More sharing options...
Nigelw Posted November 24, 2014 Author Share Posted November 24, 2014 I have to go and look at a safety divices internal cage that is fitted in a Disco on Wednesday, will be looking at the mounting points and I had already mulled over box sills and new body mounts made in 2.5mm plate at the mountings. I am not sure how reliable this quote will be but I had a chat with a company here in Holland who claim to be able to do me a full internal cage for my Disco for €950 fully fitted, it is a welded in cage so once fitted it has to be cut out unlike the SD cage that bolts in and could be removed relatively easily should I change vehicle in the future, I am yet to see how it is mounted, does it go direct to the chassis or do they strengthen the floor above the body mounts? I posed those questions but my Dutch is passable but not perfect and a trip to their works is planned next month to see some examples of their work. Quote Link to comment Share on other sites More sharing options...
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