elie boone Posted June 19, 2014 Share Posted June 19, 2014 If someone want the benefits of a cage without the difficulty of getting in and out what could be the solution ? It's all about a full cage D shape, how much strength would it loose if I cut the outer tubes ? leaving only the rounded middle tubes, and will it offer more security than a std FIA bar ? or would it become dangerous when it starts to bend ? i.e. bending inwards ? Edited by - elie boone on 19 Jun 2014 09:54:18 Link to comment Share on other sites More sharing options...
ECR Posted June 19, 2014 Share Posted June 19, 2014 Can't give an opinion on this but If I were doing it (Which I wouldn't 😬) I'd hinge the side bars from the back with a pin lock at the front. Not as good as a fully welded bar but better than nothing and would still ease entry. Link to comment Share on other sites More sharing options...
simonpa Posted June 19, 2014 Share Posted June 19, 2014 IMO, you would be better off just having a decent FIA bar than taking the sides off a cage. Where you removed tubes from the front and rear, it could alter the integrity of the remaining front/rear hoop sections. I suspect that if you had an accident, you would also risk invalidating your insurance. Just sell the cage and buy a FIA bar instead. Link to comment Share on other sites More sharing options...
elie boone Posted June 19, 2014 Author Share Posted June 19, 2014 Simonpa, that is what I am trying to find out, but you need a petty stud to make a FIA bar an FIA bar otherwise it's just a rollbar. Link to comment Share on other sites More sharing options...
Leadership Team SLR No.77 Posted June 19, 2014 Leadership Team Share Posted June 19, 2014 Elie, an FIA bar is constructed from more substantial material than a full cage, however depending on the finance available it might be worth speaking to Caged about having a "special" made using the uprated material? Stu. Link to comment Share on other sites More sharing options...
simonpa Posted June 19, 2014 Share Posted June 19, 2014 Quoting elie boone: Simonpa, that is what I am trying to find out, but you need a petty stud to make a FIA bar an FIA bar otherwise it's just a rollbar. I'm sure the later Caged bars have no facility for a petty bar, so FIA approval is for just the rear bar. All UK events I've been to that mandate an FIA bar have allowed early and late FIA bars without a petty strut (as long as they have the sticker). I would agree that a petty strut would improve protection, though! Link to comment Share on other sites More sharing options...
elie boone Posted June 19, 2014 Author Share Posted June 19, 2014 Stu, the bigger tube makes it more rigid, however construction and mounting points are also equally important. Other wise a Ariel would be 3 times more rigid than a Caterham ( 😳 hope it isn't ) Simonpa *tongue* so if I put a sticker on it's ok *tongue* I am sure that an early bar without petty stud in not FIA accepted. Link to comment Share on other sites More sharing options...
simonpa Posted June 19, 2014 Share Posted June 19, 2014 Lol Is this for track or road use? Link to comment Share on other sites More sharing options...
elie boone Posted June 19, 2014 Author Share Posted June 19, 2014 Road use but could be both Link to comment Share on other sites More sharing options...
Leadership Team SLR No.77 Posted June 19, 2014 Leadership Team Share Posted June 19, 2014 Quoting elie boone: Stu, the bigger tube makes it more rigid, however construction and mounting points are also equally important. Other wise a Ariel would be 3 times more rigid than a Caterham ( 😳 hope it isn't ) ... So it might be possible to start with what is basically an FIA bar and add similar centre D-hoops and front section as used for a cage? Stu. Link to comment Share on other sites More sharing options...
chris perry 1 Posted June 19, 2014 Share Posted June 19, 2014 Elie, The full cage is a braced/un-braced steel frame in terms of structures. The rear 'X' behind the seats acts to give the frame stability to side impacts. The 'D' over your head will transfer any side impact loads on the wind screen surround tube back onto the the rear 'X' brace. Forward and rearward impact loads will be transferred to the chassis by the rear stays and side tubes. In reality, as the whole frame is welded any load will be transferred throughout the frame. If you cut out the side bars that tie the whole frame together the cage would not be as robust and the tube diameters would increase in size to take the impact loads. I believe the MSA have recommended loading and loadcases for the design of full cages. The Caterham cage does not meet the MSA blue book requirements but has been tested to meet the required loading set by the MSA. Have a look at this link here: http://www.mjsfabrication.co.uk/roll cages Regards, Chris Perry Link to comment Share on other sites More sharing options...
elie boone Posted June 20, 2014 Author Share Posted June 20, 2014 😶🌫️ I am not going to cut up a cage, a friend talked about a cage but wanted easy access, I know that if a remove the outer tubes I compromise strength. My initial question was : without the side tube would the cage become dangerous, would the cage bent inwards if you roll it ? or with a side impact would the centre tubes be bent downwards. If I fill the triangle in the centre it would ad strength but would it be rigid enough that is the question, for sure it would be safer than just the rear bar if and only if I can get the centre part rigid enough. Maybe I should try to have a chat with the boys at RML 😳 Link to comment Share on other sites More sharing options...
Myles Posted June 20, 2014 Share Posted June 20, 2014 Although not ideal, how about a drivers-side only mod to the normal design? I.e. Keep the pax side as usual (perhaps beef it up) but take out the main fore-aft bar, leaving the d in place. A bit like what you'd have if you fitted a gull-wing, iyswim? All depends how mobile the driver is and what their risk appetite is, I guess... Link to comment Share on other sites More sharing options...
myothercarsa2cv Posted June 20, 2014 Share Posted June 20, 2014 Quoting simonpa: I'm sure the later Caged bars have no facility for a petty bar, so FIA approval is for just the rear bar. All UK events I've been to that mandate an FIA bar have allowed early and late FIA bars without a petty strut (as long as they have the sticker). They do - different mounting though. The new ones are attached to the centre of the top of the bar with two bolts. This would be my preferred option. Make sure your roll bar is actually tall enough though - Caged are very accommodating and made me a bespoke one Cost no more than a standard one (and they had to redo it 😶🌫️) Link to comment Share on other sites More sharing options...
Mike Eamer Posted June 20, 2014 Share Posted June 20, 2014 I think the best option if you want a cage over a rollbar is what someone raised about a "hinged" bar on the drivers side... as long as its well designed and the pin is suitably rated. Do dont want the hinged member seperating at the joint and becoming a "spear" in an accident... Mike Link to comment Share on other sites More sharing options...
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