exo help. Is a cross or v better

[bru21]

has anyone on here exo'd a patrol extra yet, just like some pics for ideas as it is the next step for mine as the tray is done. i dare say the most buggy like of the challenge trucks:twisted: 600mm chassis chop, with the 39 claw spare (thanks ryano) mounted above the rear winch with remote fairlead held by tube. pics will be up after painting.

WHO HAS ROLLED AND WHAT HAS WORKED PICS OF ANY WILL DO

is a x on top any better than 3 or 4 along.

and general tips would be good like is tube or flat steel triangles better for bracing corners and why etc

my main hoop is 50mm as will be the exo. (as well as 38mm) and sits clear enough of the cab. the exo wil mount to the side steps and run to the front bar.

mounting methods you have used would be good too like sleeved tube vs flanges etc but if welding it on is justifibly better bring it on

cheers bru

[J Top]

I have done 1 but I ain't high tech enough to post pics.
63mm skids, welded to flange plates then welded to the chassis. 3 outriggers
50mm main cage with a X, behind the cab, with 2 bars running down from the top corners to the rear chassis.
The front hoop is actually 2 side hoops with a link bar accross the top of the screen.
Definatly a X over the roof to keep it rigid.
The main problem, and one I havn't overcome yet, is a bar accross the bottom of the screen to hold the side hoops in in a hard dump on it's lid, its very hard to clear the wipers, open the bonnet and not have the bar 1/2 way up the screen.
J Top

[beebee]

Firstly - I don't pretend to know much about patrols but I've been involved in 3 exos (2 on mine and 1 for 83lux) on hiluxs.


I use a combination of 32 NB light, med and heavy wall (2.5, 3.2, 4.0mm respectively) pipe as well as some muffler tube thrown into the mix. The first one I built was all heavy wall but I know understand the loads better which has enabled me to build a lighter and stronger cage. The first cage took 2 complete roll overs, 1 BIG roll over and probably 4-5 flops. After the big roll that I had in the mud persuit at LCMP I had to replace the body but still just pulled the cage straight and welded it back on for woodpecker 3 weeks later. Had I not had a cage for that roll, I would have definately ended up in hospital.

I try to visualise the "impact" areas of the cage and ascess the strength required. As such, in my current cage, I have heavy wall scrub bars with heavy wall A pillar bars going from the scrub bars over the doors to meet the medium wall B pillar. The B pillar is braced with 7 pieces of muffler tube radiating from a central node. The bar above the windscreen between the A pillars is medium wall with 3 roof braces in light wall. There are 2 medium wall bars from the top of the B pillar to the rear of the chassis. And there is also a 25nb med wall lower windscreen bar along with 2 diagonal braces over the windscreen meeting at the top centre of the windscreen.

All bars are pre cambered to try and direct load axially before bending.

So far this cage hasn't been tested but I'm confident of it's strength. It's much better than my last and I know how much of a beating it took.

Hope this helps.

PS If you are looking for some photos, check the Tuff Truck competitors page.

[bru21]

thanks mate that really helped.

i have searched and found pipe sizes and stuff only not reasoning. to save the windscreen in a flop how far does the cage have to be from the a pillar, i can spare a fair bit of room due to a 4" snorkel.

will i need a b pillar bar as well as my "c" pillar bar already in place (extra cab) otherwise the span may fit many a boulder in or will i prob get away with it.

also my roof is big so i guess a cross and maybe 2 lighter (38 not 50mm) front to back bars may be needed to fill the gaps.

also i was thinking a brace over the motor joining the chassis will be better to reach through the guard then a windscreen has anyone done this?

thanks mate.

[bru21]

ok i bought the steel. i got 3.2mm 48 od only as the weight saving was negligible like <5kg as my main hoop etc was already done and it is a pain checking the tube for size, and running short of one.

i didn't get heavy wall as rocks are not my main focus.

i only got 2 lenghts so if i run short i will use 2.3 for the windscreen brace and the little ones supporting the v on the roof.

weights per 6.5m length

2.3 17 kg
2.9 21.6kg
3.2 23 kg

weight of all the exo is less than 50kg so i am a happy chappy. i will run a light as minimal to rules internal.

i will make a u from the tray hoop to the windscreen, a v on top with 38mm in the middle of the biggest viods. the a pillar will follow down to the sills. the brush guards will be added later and run to a new front bar (like that wild looking suzuki in the members with eye brows

38mm triangulation at all corners as well as 2mm sheet for sinage.

so i am starting now. i think as the body is so small particually up top compared to a gu i will allow good clearence all round and it should be sweet.

also bee bee by cambering you mean pointing the ends of the bends to the centre of the nodes as to direct the force towards the opposing corner through the centre? normally cambering means to arch so when loaded it is flat like a semi trailer, just i don't have a 3 roll bender to arch, and i think doing small bends will be worse than nothing so i will make do with my speed werx and needed corner bends.

one thing that pisses me off is bluescope stopped making 50.8mm tube in 3 mm wall so the dies aren't as nice a fit on the 48, wish i bought the pipe dies but i had used them when i had found this out ( the steel was comming in for 6+mths

cheers bru

cheers bru

[beebee]

also bee bee by cambering you mean pointing the ends of the bends to the centre of the nodes as to direct the force towards the opposing corner through the centre? normally cambering means to arch so when loaded it is flat like a semi trailer, just i don't have a 3 roll bender to arch, and i think doing small bends will be worse than nothing so i will make do with my speed werx and needed corner bends.

I was referring to the scenario you suggested with the semi trailers. By peaking the bars in the middle or by placing a bend just before but flowing into the node, I believe the distance between the nodes (or the hypotenuse) must streach before the bar can significantly deform or kink. This is only my unsupported theory but it makes sense to me. I have used this primarily in the barwork above the roof. As I see it, this will be of benifit where the bars are more likely to take a direct load (perpendicular to their axis) resulting in a kinking effect rather than an axial compression or tension forse. Probably only of use for external cages that come into direct contact with rocks etc.

Hope that made some sense

[bru21]

thanks mate, i understand.

gq's suck for mounting the a pillar to the chassis as there is no box section where it needs to go. i will mount it to the side steps and run a length of 50x50 along the transfer case crossmember and support the side steps

[bru21]

its nearly finished, i started sat lunch and finished at 10pm tonight, worked solid. i ended up with hoops from the roll bar along the sill and down the a pilar. a hoop over the screen. still need to put the v on the roof i ran out of steel. and fit the lower screen brace after i put the bonnet back on. i put sleeve joins on the a pillar. put heaps of thought into it and all the compound bends came out sweet.

what sort of panel clearence do others have. i made mine at least 50mm (40mm at roof sills) as my tyres stick out so far that i felt it would never hit anything

cheers bru

[Bartso]

post up pics mate as im doing the same thing very soon and would like to see how yours turned out

[bru21]

be paitent all will be revealed soon!

[83 lux]

its nearly finished, i started sat lunch and finished at 10pm tonight, worked solid. i ended up with hoops from the roll bar along the sill and down the a pilar. a hoop over the screen. still need to put the v on the roof i ran out of steel. and fit the lower screen brace after i put the bonnet back on. i put sleeve joins on the a pillar. put heaps of thought into it and all the compound bends came out sweet.

what sort of panel clearence do others have. i made mine at least 50mm (40mm at roof sills) as my tyres stick out so far that i felt it would never hit anything

cheers bru

About 10-15mm on the roof and 20-30 for the rest

[bru21]

is that enough? or does it touch when you roll. i guess an extracab gq is a lot longer in the roof

cheers bru

[83 lux]

is that enough? or does it touch when you roll. i guess an extracab gq is a lot longer in the roof

cheers bru

i have a dual cab
and i guess it might touch when i roll but all it is therefore is to safe my life not my cars paint work
even thou it have safed that one moe then once

below is a pic of the roof

[bluemq]

You could use a bit more cross bracing across the back, would probably help with the touching.

But true - it's there for your life, not the paint.

[N*A*M]

also bee bee by cambering you mean pointing the ends of the bends to the centre of the nodes as to direct the force towards the opposing corner through the centre? normally cambering means to arch so when loaded it is flat like a semi trailer, just i don't have a 3 roll bender to arch, and i think doing small bends will be worse than nothing so i will make do with my speed werx and needed corner bends.

I was referring to the scenario you suggested with the semi trailers. By peaking the bars in the middle or by placing a bend just before but flowing into the node, I believe the distance between the nodes (or the hypotenuse) must streach before the bar can significantly deform or kink. This is only my unsupported theory but it makes sense to me. I have used this primarily in the barwork above the roof. As I see it, this will be of benifit where the bars are more likely to take a direct load (perpendicular to their axis) resulting in a kinking effect rather than an axial compression or tension forse. Probably only of use for external cages that come into direct contact with rocks etc.

Hope that made some sense

i really think this is a great technique. carlton did it on the mav buggy and it's been flopped and rolled so many times. the bars will dent at the point of impact but the cage is still quite plumb. i will definitely apply this technique in the future. the only downside is that it makes it difficult to panel the roof of a with a single sheet. but that's trivial.

[bru21]

i think it will make for a softer roll too rather than a jar.

also i haven't done the roof bracing. what is the best. i was going to use a triangle reaching to the centre of the windscreen and truss the corners as to make all the remaining holes smaller. or is an asterix better

cheers bru

[beebee]

It all depends

I assumed that the most likely load in the roof plane would come from around the A pillar so I made my bracing connect at that node on each side and in the center of the B pillar in the V format. However I also placed a center bar from the middle of the B to the middle of the A pillars. This closed off much of the open space on the roof. I made sure I had a bar directly over my head but still plan to put some steel plate up there some day I also pre-cambered these members so that any impact load would cause the bars to elongate before kinking thus trying to streach the roof plane. This transfers the load along the axis of the members and should require less section strength.....hopefully

[bru21]

thanks mate. i was thinking of the v making a central node above the screen as to tringulate the v, bracing to the stronger b pillar hoop. the two ends would then flow on to the braces down the tray to the rear chassis. i thought that when rolling at speed would not bend the b pillar where it is unsupported in the centre.

then run bars from the a pilar corners to the centre or the roof.

i will post some pics when i get a minute.

cheers bru