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Internal roll cages

Posted: Sun Feb 22, 2015 4:59 pm
by Matt
Hi guys, I'm trying to keep my Sj as subtle as possible and I want a bit more protection. I am seriously considering the internal rollbar/cage route but I need some other opinions, I personally am not a fan of external cages unless you are doing challenge events etc. so the plan was to go internal, i like the look of a good internal cage but it seems like buying one from America is going to cost me over £1200 are there any better options?

Re: Internal roll cages

Posted: Sun Feb 22, 2015 8:08 pm
by mike harris
Buy mine for £300 then?!

Re: Internal roll cages

Posted: Sun Feb 22, 2015 10:56 pm
by twiss
Tbh I think unless you are going trailing and just want a bit of protection in case you fall over, a decent rollbar will give you some protection in a low speed side roll.
An end over end roll is a different story though but I try not to get into that situation...
A full external rollcage is desirable as it protects the bodywork as well, something an internal won't do anyway

Re: Internal roll cages

Posted: Sun Feb 22, 2015 11:35 pm
by gamble63
like twiss said, if you have an internal and do roll it the car is f**ked and youll have to take the cage out, a decent exo cage would be better for the truck.

look at this jimny with full internal cage after it has this roll haha

https://www.youtube.com/watch?v=MqqfvtxTzy4

Re: Internal roll cages

Posted: Mon Feb 23, 2015 12:01 am
by ScottieJ
An external cage only protects the bodywork where the tubes are......so if the ground isn't flat or you roll onto a tree stump/Rock it wont stop much damage, seen plenty of exo caged sjs with massive dents :lol:
It's also much easier to make a stronger cage going internal as you can add triangulation without going through the bodywork.
Personally I wouldn't want any cage without at least an X in the B-hoop, I've seen exo cages without cross braces turn into a parallelogram wrecking the body after a rollover, bray's old Lj80 cage deformed after a roll, if the roll was much worse it could have completely failed.
Image

Image

It's actually shifted the whole back end of the body, it's got a box section body lift that is no longer square.

I'm bending up an internal cage for the Lwb, then fitting rock sliders to help protect the bodywork from trees etc.

I want a cage that will save my life in a rollover in the worst case scenario not just a gentle flop. you can replace a suzuki body but you only have one life.

Re: Internal roll cages

Posted: Mon Feb 23, 2015 12:28 am
by Anton
I'd rather have a good internal cage, personally. For all the same reasons Scottie mentioned.

Having said that, I did drool a bit at this.

What kind of weight is a cage adding?

Re: Internal roll cages

Posted: Mon Feb 23, 2015 12:46 am
by ScottieJ
Matt's cage is a pretty good design with the internal cross brace.

All depends on the material Anton.

I'm going to be using CDS for my cage and being internal I can use 2.65mm wall, if I build a cage with external sections or tubes that are likely to get hit, those sections will be 3.25mm wall.

44.45x 2.65mm wall 2.72kg/m
44.45x3.25mm 3.30kg/m

So if you say an average (very basic) Sj external cage would probably use a minimum of 16m of tube, if you used 44.45x3.25 that would be 52.8kg, not including outriggers and rock sliders.

A lot of places use larger OD tube as well, 2"/50.8x3.25mm is 3.81kg/m

Re: Internal roll cages

Posted: Mon Feb 23, 2015 1:02 am
by Anton
52kg isn't the end of the world, but on a 900kg vehicle, adding 50kg up that high - does it mess with vehicle stability at all?

I want to assume not (thinking about Mike's monster) but I can't help but feel it's a lot of weight to add up high.

Re: Internal roll cages

Posted: Mon Feb 23, 2015 9:31 am
by ROBBIE
I had an internal cage in my old soft top, bit ruff but I didn't build it, was in there when it got it. When I rolled it, was a nice slow one, was so happy that it was. I had to replace parts, but its not hard on a soft top, 2 doors roof hoop and screen frame, better than being squashed :D

Re: Internal roll cages

Posted: Mon Feb 23, 2015 9:55 am
by ScottieJ
Anton wrote:52kg isn't the end of the world, but on a 900kg vehicle, adding 50kg up that high - does it mess with vehicle stability at all?

I want to assume not (thinking about Mike's monster) but I can't help but feel it's a lot of weight to add up high.
Not much of the cage weight is up high though, I would rather a bit of extra weight up top than to get squashed in a roll.