Is the single roll hoop on a MK Indy strong enough to protect driver in a roll over ? should it not be a triangulated bar with rear stays.

No and yes.

The single hoop is a token gesture.

I had a single roll hoop on my MK Indy. IMHO it might protect occupants in a sideways roll, but even then ought to have internal triangulation to strengthen it. In the event of fore/aft force I'd say it would fail. If reinforced with rear members then the rear members should go to the lower chassis itself (from memory there wasn't an upper hoop in the rear of the chassis anyway.

What do people do if they see a car thats perfect in every other way, can an RAC type bar be retro fitted without dismantling the car too much? reason for asking is i have seen a really nice car that ticks all the boxes except it only has the fairly puny looking roll hoop.

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Originally posted by limpetminer
What do people do if they see a car thats perfect in every other way, can an RAC type bar be retro fitted without dismantling the car too much? reason for asking is i have seen a really nice car that ticks all the boxes except it only has the fairly puny looking roll hoop.

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I was thinking about this - its obviously not as good as a full roll cage, but id like to make the best of what ive got, in terms of a single hoop.

Without dismantling the car too much, id have thought some additional bracing down to the rear chassis, and 45 degree struts going into the cockpit - could help.
Surely the the second best option to a full cage, is to have a roll bar which will not collapse if the car rolls. At least offering some protection.

Going to do mine for the same reason, it just doesn't look safe with a single hoop, plus I'd like to do some sprints/hullclimbs, so I want to get a cage that will satisfy MSA regs as well.

Think the rear body tub will need removing. Mine doe have a hoop around the top of the rear body, but it doesn't appear to be either strong enough or linked to the lower chassis members.

Still haven't decided where to get the cage from though ....

If you intend on doing msa sprints then make sure the cage or roll over protection is done by an msa approved manufacturer like Jeff w had to do. There's serious issues with the msa and roll bars at the moment,so better safe than sorry unfortunately.

Thanks Mate, will do, got any suggestions as to a good manufacturer ?

I'd ask Jeff Wiltshire.his did not comply on his Phoenix but had a new one made. log onto uphillracers website and have a read of the thread 'roll bar single seaters' and see what a total mess the msa are making with roll bar regs in speed events.

Thanks Mate will do

So, still doing mods to the car, but getting closer now.

Decided to modify the existing cage myself to start with, but to make the mounts suitable for an MSA approved cage if and when I decide to do some comp stuff in it. Welded some plates in the rear corners to start with, 3mm thick. Then got some suitable sized tube, and tacked some rear stays to the existing bar, took the whole thing off, and finished of the welds, then welded a diagonal in place, so it looks like this at the moment:


[img]
Roll cage mods [/img]

Put acouple of small bts of plate underneath the legs for support, but will next weld some permanent feet on