Roll Cage Hoop X-bracing design

[ltwt1981]

I don't think it will pass scrutineering without a cross brace.

Also rear stays should be within the rear axle line.

Correct me if I am wrong.

[bishbosh]

Try and get the rear stays to go directly to the chassis.

[simonr]

Just for info, yacht insurance demands 5 yearly renewal for racing yachts, 15 years for cruising yachts.

That's interesting info.

I kind of agree with the durability issue - although steel cable in particular is used in a lot of structures for this purpose.

One advantage in general is if the structure does deform, you may be able to straighten it by re-tensioning all the wires (like tensioning the spokes of a wheel).

Another possibility would be a removable bar? I intended making a removable internal cross brace for mine - but after I did the calculations & FEA, decided it was not necessary for the kind of roll likely to be experienced.

Si

[DefcoL]

Hi Gav

a few pics of the build process over on Difflock

http://forum.difflock.com/viewtopic.php?t=8061

Not taken photos of cage yet as its still a work in progress (hence this thread!) I will take some when it looks a bit more "finished" so that the full integration with the tray and chassis is clear.

Cheers

Mark

???????????????????Tim... that trayback is being built concurrently by a lad called Russel. We have met at various Challenge events and kind of dared each other to go for the full trayback. We started our builds within a few weeks of each other but he seems to be getting on quicker! But then mine will be a work of art (literally) when I finish........

__________________________________

Hi Mark.. your build is coming along nicly and a well thought out tray... Just wondered why you refer to me as Russel?

who is He? Like the lad part

Cant wait to see your work of art in action..

LAWRENCE (its my name)

[LandyManLuke]

Looks like wires are consigned to vapour-trucks then

[Orgasmic Farmer]

Sorry Lawrence. Crossed wires. Thers a Russel on here with a similar colour Disco to yours and I somehow got it in my head that you both had the same name. Lawrence - Russel..... sounds similar if you say em quick enough

My excuse is i'm 40 and the old brain ain't what it used to be

[DefcoL]

Sorry Lawrence. Crossed wires. Thers a Russel on here with a similar colour Disco to yours and I somehow got it in my head that you both had the same name. Lawrence - Russel..... sounds similar if you say em quick enough

My excuse is i'm 40 and the old brain ain't what it used to be

No probs Mary... wait till you reach 50, you might even get the genders wrong

the organics seem to be working then.....

What colour are you going to finish your truck in? are you going to go for the very standard Black for the tray?

personly I think mine will perform better with thr tray in a mid range metalic grey with silver scratches

[Mark90]

The Tray is open to the rear to accommodate the spare and to make winch servicing a bit easier

How about a removable bolt in section?

Also what Bish says about the rear stays makes sense, especially as the box section they currently mount on leans out already in the direction a load will be in the event of a roll.

[Orgasmic Farmer]

Colour of the truck is Code 9 i'm afriad Lawrence.

Mark and Bish. I hear what you're saying and in an ideal world I would do this. BUT the chassis is only a maximum of about 28 inches wide whereas a Simex is 36 making it impossible to keep the tyre below and tray and brace to the chassis!> I have checked the photos of the Interclub challenge and well over 50% of the trucks that took part did not brace directly to chassis and NONE of the traybacks did so I guess I will be in good company

I am hopwever trying to triangulate the box on which the braces sit back to the main hoop support in an attampt to give it a bit more structure. Looking at what others have done this in itsself is a belt and braces approach.

In answer to LTWT 1981 there is, as yet, (as far as I am aware) no requirement to have a roll cage on any of the challenge events I have yet entered so cage design is not governed by MSA bluebook rules. If this would ever change then I, and almost everyone else on the challenge scene, would appear to have some redesigning to do :o

[DefcoL]

Colour of the truck is Code 9 i'm afriad Lawrence.

Code 9?

is that a colour or stealth mode

[ltwt1981]

Point taken, I always look at cages from an MSA view as I mostly do race cars.

Another area to think about is bulkheads in general as we see loads with holes in, it has to be solid to prevent access of fuel, oils, fire etc.

[Hybrid_From_Hell]

A Huge amount of work there

Anyway, FWIW re the cage and the rear stays I would seriously consider seeing if there is some way you can get them down to the chassis or even into the back edge of the winch tray / chassis, the thing I notice (and it could be the pic misleading me) is the stays are looking as tho they are going to join some sort on box section, yet this box is tilted backwards ?

If thats the case and good hard roll would see those angles move in the same direction, making the stays collapse.

Nige T is a MSA Scrutineer, the MSA book isn't bad and designs are strong, if you can "Sort of" ioncorporate as much of those designs as you can in the main framework - this way your emcorporating good solid design structures.

Just a thought, but nice work anyway

Nige

[dirtydiesel]

As nige has allready said think very very seriously about getting the rear stays to the chassis, as well as getting as much triangulation into the rear hoop as is possible.

IMHO i wouldn't compremise the cage design around the rear window.

[gav-]

landyluke, sorry to ask what bender did u use?? the workmanship looks really good

[DefcoL]

how is your build coming along Mark?

Any more pics yet?

R Lawrence

[LandyManLuke]

landyluke, sorry to ask what bender did u use?? the workmanship looks really good

Have you confused me with someone else? Mr O. farmer perhaps?

[gav-]

doh doh doh, so many names!!!

Yes I did mean O.Farmer - sorry landyluke

[Orgasmic Farmer]

doh doh doh, so many names!!!

Yes I did mean O.Farmer - sorry landyluke

who me? Sorry was sleeping

The bender I used was a sealey 12 ton pipe bender bought new off Ebay for princely sum of £59. Works fine (easier than expected) but noticed that the rollers do leave a tiny dent in the tube to mark their presence.

[gav-]

Am glad u said that. I have one just like that!!!

[DefcoL]

who me? Sorry was sleeping

The bender I used was a sealey 12 ton pipe bender bought new off Ebay for princely sum of £59. Works fine (easier than expected) but noticed that the rollers do leave a tiny dent in the tube to mark their presence.

Mark..

I got the same results (from the one I borrowed) on the first bend then I moved the rollers further apart, massive improvment but still got some kinking on innner rad (but not on all).

Also the formers leave a lot to be desired as they seemed to splay slightly and we got some flattening on outter rad.

having said all that, I am very pleased with the results as it was my first ever tube bending and after all it is only an offroader

[biasbilt]

it was my first ever tube bending and after all it is only an offroader

Yeah, and it's only your life, and your Land Rover only weighs 2 tons and therefore you shouldn't cut any corners on what could be a life saving part of your car. Although a cage is there to protect you in an accident, it will also give you the confidence to do things that you might not otherwise have driven, and thereby expose yourself to as greater risk of a roll. If you are not able to produce accurate bends with a minimum of deformation (0.9 ratio between major and minor diameters allowed by MSA rules) then get someone else to bend the cage for you.

Toby

[DefcoL]

Yeah, and it's only your life, and your Land Rover only weighs 2 tons and therefore you shouldn't cut any corners on what could be a life saving part of your car. Although a cage is there to protect you in an accident, it will also give you the confidence to do things that you might not otherwise have driven, and thereby expose yourself to as greater risk of a roll. If you are not able to produce accurate bends with a minimum of deformation (0.9 ratio between major and minor diameters allowed by MSA rules) then get someone else to bend the cage for you.

Toby

Lighten up sweeheart and note the --- --- it was there for a reason

please note I did not say how much of kinky flatening or to what degree

It realy did work out OK

[Turbocharger]

Nice frame! I don't think much of the wooden chassis though...

I think Bias's point is that the devil is in the detail, it's not just a case of kinking some steel round your knee and splattering it with a welder. One man's kink is another man's "witness mark".

(I want a garage like yours)

[DefcoL]

Nice frame! I don't think much of the wooden chassis though...

I think Bias's point is that the devil is in the detail, it's not just a case of kinking some steel round your knee and splattering it with a welder. One man's kink is another man's "witness mark".

(I want a garage like yours)

Thanks...

The cage has worked well and the detail took many hours of consideration prior to fabrication. I ran several designs for both body and cage in AutoCAD

and Photoshop.

As normal designs are best when organic and this one defiantly developed from original idea. I say that as a designer. I also hold mechanical engineering

qualifications from 1974 so Have a good grounding in metal work, that said I didn't do the important welding , my mate (welder fabricator) lent a big hand for ten of the 56 full days it has so far taken.

here's a link to the thread where there are more pics of the finished cage and the disco conversion.

Unfortunately the garage is not mine, it belongs to another mate who also offroads.

http://forums.lr4x4.com/index.php?showtopi...st&p=143413

Regards

Lawrence

[biasbilt]

I'm not getting my knickers in a twist and it looks like you're doing a great job. But to someone else reading your post, they might just assume that "it'll do" with poor bends/design, and not do the design/fabrication properly (which it looks like you've done).

At the moment, there are lots of people building cages that aren't properly designed, with bent stays, tubes not meeting properly at nodes, untriangulated areas etc, and while these are probably (and have been proven to be) strong enough, if they were just copied, there could be potential for disaster. That's why I always recommend that (and build) cages to the MSA specs, as they are proven design principles.