CroMo Cages

[gslrallysport]

umm.... the use of Cromo in roll cages is a subject of a completely separate thread if you want to go there... I won't get get started, but suffice to say that there's a reason why the FIA has now banned it in Group N/A... (One of the few things the FIA has got right of recent times).

[auzvectra]

umm.... the use of Cromo in roll cages is a subject of a completely separate thread if you want to go there... I won't get get started, but suffice to say that there's a reason why the FIA has now banned it in Group N/A... (One of the few things the FIA has got right of recent times).

yeh i heard something similar to this too. it cant be used for chassis now either. cant memba the exacts of it, but was sompthin along the lines of becomes very brittle under stress. could be off, as i cant memba where i hear it. pretty sure it was a chassis builder.

[gslrallysport]

You're pretty much on the money... Without starting a big thread about it, the simplified version is that there isn't cage builder in Aus that knows how to weld it properly, the welds are self hardening and so becomes ridiculously brittle after 2-3 years of their own accord, and it's higher tensile strength (which is what all the pro-cromo cage builders will use to talk you into it) actually means that the cage is likely to snap (the already weakened) welds rather than just deform bars slightly...

As I said, there's a reason why the FIA banned it on safety grounds, and why it has to be unpainted and inspected for cracks regularly when used in drag racing. It's dangerous, and for all the useless crap that CAMS have blindly followed the FIA with over the years which they didn't need to, CAMS still haven't followed the FIA in banning it's use locally in PRC and tarmac gravel and rally cars...

I don't want to continue this on in this thread, but please, if anybody wants to discuss it start a new thread and I'll be happy to contribute. I just like to make a point of making sure that anybody who buys a cromo cage that's more than 2-3 years old, is aware of their dangers, and that they really should be inspected for cracks. Thus why I asked initially about what it had, not to hi-jack the thread with anti-cromo propaganda! :p

[gman]

Started new thread cause it was a massive hijack and it seemed a few people might be interested...

So in short, CroMo = bad as its actually too stiff and is more likely to snap, espcially around the welds as they age, than CDS tube which will bend/deform and disapate the energy better....

So you want a cage that deforms slightly to absorb energy and NOT catastrophically fail (snap) like CroMo might, but still maintains enough integrity to ensure minimal intrusion into the occupant survival space and allow survival of the inital impact and egress post event??