russ1 Posted January 28, 2009 Share Posted January 28, 2009 Afternoon When i have been looking through my pics of different challenge events i have seen a few different cage designs, most of them have the same kind of design for the front hoop. Sorry Jim looking at jims (gigglepin) truck the design for his truck looks as if it would be a better idea for my truck seems as if the bar over the windscreen is separate the the main front hoop I have always thought the front hoop needs to be 1 complete bar. If the way jims truck is done is fine that would save me a lot of bother with my truck. Thanks Quote Link to comment Share on other sites More sharing options...
Lara Posted January 28, 2009 Share Posted January 28, 2009 Hi. There is no set rule for roll cage design, to be honest it boils down to this. If you feel competent to design and build a LIFE SUPPORTING structure on your vehicle then you probably know the answer to your question your self. (not meaning any offense what so ever, I don't know your background) There are several conflicting ideas toward roll cages and it all depends on what your intended use is. Possibilities are. a. To protect the occupants, = Strong design with no or few weak points and tubes triangulated as much as possible, strong tube but deformable without fracture in severe impacts. b. To protect the vehicle, = Strong design with no or few weak points and tubes triangulated as much as possible, as strong tube as possible. c. To look cool, = lots of rolled bends and fancy stuff. d. To be part of the supporting structure to add strength or be part of the chassis, = Strong design with no or few weak points and tubes triangulated as much as possible, as strong tube as possible. e. Do all of the above (except c cos that's for the yanks ) with as little weight as possible. = Intelligent use of materials and good design. Jim's cage was designed to do a purpose, and does that to the level he is satisfied with, In order to answer your question you would first need to know what criteria Jim or the manufacturers had in mind when it was designed and built. Maybe it is just a fancy light bar? or maybe the whole cage is made from special hi tec Ti-xyz-ium? Lara. Quote Link to comment Share on other sites More sharing options...
Dave W Posted January 28, 2009 Share Posted January 28, 2009 There is no set rule for roll cage design, Apart from the designs approved by the MSA/FIA where the rules and regulations are very specific and Jim's design doesn't meet any of them Only a problem if you want to compete in an MSA event that requires a roll cage of course. The single piece front hoop thing comes from the ALRC whose designs were incorporated into the MSA regs rather sharpish when it was realised that all their cages were about to be "illegal" for MSA use My cage doesn't meet full MSA regs either as far as I can tell but it's designed to do a job, as you point out. Quote Link to comment Share on other sites More sharing options...
plasticbadger Posted January 28, 2009 Share Posted January 28, 2009 The original MSA / FIA regs all required a separate section over the windscreen with the front 'legs' extending back to the main hoop. But as Dave says, this was changed to allow the ALRC type front hoop (one piece front legs and accross windscreen). The most critical thing is that the main hoop (behind the driver) is in one piece, chassis mounted and triangulated. Everything else is secondary. Quote Link to comment Share on other sites More sharing options...
Lara Posted January 29, 2009 Share Posted January 29, 2009 To be honest, the MSA rules for roll cages give you an awful lot of leeway! they are a "minimum" guide for MSA run events but are only there to guide you to what they see as safe enough, they are certainly not blueprints for success. Again though, depends on the cages ultimate intended use. Most Landrover ones are there to protect the vehicle as much as the occupants. Lara Quote Link to comment Share on other sites More sharing options...
nicks90 Posted January 29, 2009 Share Posted January 29, 2009 if challenge events - like this years muddy truckers - are being run under MSA regs, surely that means alot of competitors (including you dave) wont pass scrutineering! Quote Link to comment Share on other sites More sharing options...
Lara Posted January 29, 2009 Share Posted January 29, 2009 MSA regs don't ask for rollcages on this type of event. Shouldn't be a problem. Lara Quote Link to comment Share on other sites More sharing options...
Hybrid_From_Hell Posted January 29, 2009 Share Posted January 29, 2009 IMHO As to if you NEED MSA Cage spec or not thats one thing... But - Do bear in mind that the MSA Styles of cage design etc have been er, how shall we say... er...been "Lovingly Pre- Tested" by many which we as new cage owners can take the benefit of, so if we ever do, we should again benefit from those who went before us Again, IMVHO - A Big "Eeeeeeeeeek Feeeeeeeeeeeeeeeeeeeeeerkkingell" moment .....is not the time to be testing your 'design' of cage Nige Quote Link to comment Share on other sites More sharing options...
SiWhite Posted January 29, 2009 Share Posted January 29, 2009 How come he has a strap on the front? Is he stuck? Quote Link to comment Share on other sites More sharing options...
JST Posted January 29, 2009 Share Posted January 29, 2009 How come he has a strap on the front? Is he stuck? hes probably towing a 20T truck out of a puddle that we cant see........... does look that way anyway - glad you said it Quote Link to comment Share on other sites More sharing options...
russ1 Posted January 29, 2009 Author Share Posted January 29, 2009 hes probably towing a 20T truck out of a puddle that we cant see...........does look that way anyway - glad you said it It was just after he killed his gearbox at tay. had to be to dragged back to the main area. Quote Link to comment Share on other sites More sharing options...
T1G UP Posted January 29, 2009 Share Posted January 29, 2009 IMO it's a good idea to start with a proven cage design, cheaper aswell, and "add" to it.if you like the hoop over the lights this can be added and not alter the strength of the cage toooooo much. Quote Link to comment Share on other sites More sharing options...
russ1 Posted January 29, 2009 Author Share Posted January 29, 2009 The reason that idea would be better is i have a rear mounted rad and have a cooling duct above the windscreen same kind of idea as a tomcat etc The way jims cage is the bar across the top of the screen will miss the duct If anyone has any other ideas fell free to fire them over. Russ Quote Link to comment Share on other sites More sharing options...
Daan Posted January 30, 2009 Share Posted January 30, 2009 Bent backstays are the work of the devil. Proper triangulation is the way forward. The shape of the main hoop, with the bend coming back onto itself is a rather bad way of doing things. I know it is in the arc rules, and nearly all cages are like that, but having seen FEA analysis on that, its a bad solution. Daan Quote Link to comment Share on other sites More sharing options...
bishbosh Posted January 30, 2009 Share Posted January 30, 2009 Bent backstays are the work of the devil. Proper triangulation is the way forward. Hear hear!!! Quote Link to comment Share on other sites More sharing options...
Lara Posted January 30, 2009 Share Posted January 30, 2009 I agree in principal but again you really must include the full intended purpose when you judge, For strength triangulation is obviously the most important consideration. For safety, sometimes it is not! Some people build a weak point into their design as in a "crush" zone, some people brag about FEA designed cages and then remove bars in silly places and the driving compartment turns into the crush zone! all sorts of things come into play. This is growing into a sport where at the top level you are going to use your cage! and probably for more than one purpose. We need to consider this! Jim's cage may or may not be your cup of tea, for sure in a big roll it will deform, maybe he wants that? I for one would want the cage to bend rather than my brain (if I had one) get turned to mush. How much the deformation and at what load is down to the designer and the person paying the bill. Not everyone needs or wants a Sherman tank! Horses for courses! Lara Quote Link to comment Share on other sites More sharing options...
Dave W Posted January 30, 2009 Share Posted January 30, 2009 All cages are a compromise between ultimate safety and practicality. Whilst some designs aren't the ideal they can make for a much more practical vehicle if you need a multi-purpose vehicle. When I had my cage built I had a choice between storage and practicality or going for a full MSA spec. In the end I went for the former simply because I'd spent too many years struggling around an MSA design that screwed up everything I wanted to do with my vehicle. My current design gives maximum storage for camping gear, food, clothing, spares and allows me to easily slot an Ifor Williams or crew cab soft top on the back if I need more storage for long distance touring. My comp motor even gets to tow the caravan sometimes ! We're not competing in high speed events and I've triangulated the rear stays to give the main hoop further support and there is also triangulation form the front hoop to resist the cage going into "shear". Having said all that a close look at my main hoop will also reveal lugs for fitting by the book MSA spec rear stays should I need to at some point in the future ! Quote Link to comment Share on other sites More sharing options...
carl hurst Posted January 30, 2009 Share Posted January 30, 2009 I went this way to get over the bent rear stay issue as i'me not a fan of them, may not pas msa but is triangulated, lots of room under tray for fuel tank, rad, winch etc, Carl. Quote Link to comment Share on other sites More sharing options...
bishbosh Posted January 31, 2009 Share Posted January 31, 2009 I would argue that whay you have done is perfectly acceptable Carl - the doubled up box section braces effectlvely extend the chassis and form a good rigid node for your tubework to connect to. Agree the MSA may not like it, but I think it looks safe. Quote Link to comment Share on other sites More sharing options...
Hybrid_From_Hell Posted January 31, 2009 Share Posted January 31, 2009 ^^^ Well, FWIW as to if they like it or not I admire the qulaity of the fab work there - and the numerous hours that have gone into into Nige Quote Link to comment Share on other sites More sharing options...
Steve 90 Posted January 31, 2009 Share Posted January 31, 2009 Yep, As Nige say's. Nice work Carl. Quote Link to comment Share on other sites More sharing options...
carl hurst Posted January 31, 2009 Share Posted January 31, 2009 Russ, If you need any more photos or info i can post them on here, Carl. Quote Link to comment Share on other sites More sharing options...
russ1 Posted January 31, 2009 Author Share Posted January 31, 2009 Russ, If you need any more photos or info i can post them on here,Carl. Fell free to post your pics up mate Be nice to see your a overall view of your truck! Its mainly the front hoop thats causing problems with the cooling duct Found this pic and petal has the same kind of idea for the duct as mine but still has the front hoop made out of 1 bar. Quote Link to comment Share on other sites More sharing options...
dollythelw Posted February 1, 2009 Share Posted February 1, 2009 it wasnt a tricky problem to solve - even back then we've noticed cars weigh less if you dont add a load of "fashion" pipes, nice tow strap though Quote Link to comment Share on other sites More sharing options...
will_warne Posted February 1, 2009 Share Posted February 1, 2009 Russ, my advice on the cage is take a big stack of paper and a pen and start sketching as many different designs as you can and then, as Jez said, remove as many bits of tube as possible that do little for the strength of the cage - basically just keep at it until you think you're done then leave it for a week and have another go. If you end up with something that has good triangulation of the cab and minimal bends you'll have a cage that'll do as it's designed. Quote Link to comment Share on other sites More sharing options...
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