I found a good deal on a used roll cage from an FD that caught fire and burned up.

Would the temperature inside the cabin get hot enough to actually weaken steel tubing?

 

It's a safety item. Don't do it unless you're building a show car that barely sees pavement.

 

Why?

I'm not convinced a car interior will burn long enough or cool fast enough to harden a roll cage.
If anything, it might temper it, instead...

 

unless its a bolt in cage, its also really hard to get the old cage out and back in the new car and still be legal

 

question (post#1) and answer (post #3) sounds like it came from 2 different people despite using the same account lol

But for what it's worth, it is very possible for a sudden cool down when its hosed down by the fire truck and therefore quench the material. I obviously do not know what happened so whether its possible or not, its hard to say from just a forum post.

you can find someone who can do a hardness test locally and test it.
OR avoid the headache altogether and invest in a proper roll cage.

 

If you’re willing to risk your life on it then there’s no need to have one at all …

.

 

I'm just asking for the sake of argument! I'm curious about the metallurgy connotations.

For what it's worth, it's a quarter the price of an equivalent cage new, which is why I am so tempted. My favorite track technically requires you to have a four-point cage if you go faster than 1'40" to do their races (which I do).

 

It's a bolt in, of course.

 

most of us understand the requirement, but the point of my previous post is perhaps lost in translation ….

there are sound reasons for not re-using a helmet that takes a hit or multi-point harness after a big impact though they may appear fine otherwise afterward.

so again, if you’re into risks then then there's no point in guarding against them at all. If all you care about is meeting the regulation requirement and not really protecting yourself the best minimum safety measures possible then it’s really just the same thing.

To wit, why ask the question and then turn around to argue against the more costly option? If you honestly believe that then there was zero point in starting this thread rather than having just bought and installed it on the basis of your own counter-reply.
.

 

I only started the thread because there was a chance an expert might tell me "nope, the heat of a car fire isn't going to do much to a roll cage. might rust, though."

I don't think the helmet or belt comparison is entirely fair. Obviously I'm not going to buy a roll cage from a car that has been crashed. This is more like "don't let race tires freeze." It's more subtle.

 

Much like with the fire, it's all relative. i wouldn't have much faith in an "expert" who will answer your question, given how little information is provided with your post.

 

i'd go look at it, if the fire touched the cage, i'd skip it. chances are though that the fire was in the engine bay or something, and didn't get anywhere near the cage.

 

The whole car was toasty. Come to think of it, a new equivalent cage is only a couple hundred dollars more...
I am still debating whether I want a through-dash or around-dash cage.
I don't mind the extra work to install it, but I suspect a through dash might actually be worse in terms of leg clearance.
Roll cages can affect your ability to heel toe on RHD FDs.

 

I was using the cusco safety21 rollcage, the one that goes around the dashboard and i cant say i was very pleased with the leg clearance on my rhd fd.
i couldnt do heel and toe with it.

 

I was considering that one. They don't actually make a through-dash (at least not any more), but other companies do. Do you think a through-dash would be better, or would it basically be a wash?

 

I am under the impression that it was offered in the past but i could be wrong.
i am not entirely sure that the through dash would give you more clearance for your right foot but i do not recall seeing the cusco through dash version in person so i dont have a clear picture .
It might, but that area is quite small, i am having a hard time visualizing where would it mount to offer no obstruction.

 

Wrong country, those dodgy dog leg cages they sell there go cheap here! They're illegal for street use - and don't meet FIA minimums and hence not permitted in anything much beyond lapping locally.

Certainly wasn't a pretzel, and nothing exotic, a 1020 tube frame car was in a workshop fire here, lived to run another day after engineering inspection.....intensity and duration is probably the biggest factor in salvageability.

 

you don’t have to be an expert to understand that the one fundamental point about safety is to mitigate risk.

a penny wise, a pound foolish … it’s one thing to use it in a lower speed autocross/gymkana application, it’s another to use in an application where the vehicle can run into, or be run into, objects at high speed.

.

 

I don’t think anyone even sells FIA legal cage kits for anything but current cars. But if course it has to be installed by an expert to be FIA legal, anyway, IIRC. They’re also like $5,000.

You're not wrong.


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They probably did back in the day, but the current catalog only has around-dash cages. Even their "works-type" 10-12 pound cages are around-dash.

Come to think of it, if I install a cage, I'm probably going to need a fire suit and a quick release, because it will be much harder to get out of the car.
It's already requires a bit of gymnastics to get in and out.

 

You can be compliant over here manufacturing and welding in your own cage, just as long as you use a standard FIA drawing for placement of reinforcement tubing, etc. If you start using T45, Docol, 4130 or the German vanadium stuff, that's where you're in a world of hip pocket pain with engineers.

Coals to Newcastle with shipping to Japan, but I know these bolt-ins have been sold offshore https://www.agi-precision.com.au/pro...mazda/rx-7-fd/

 

As to be expected of 'Straya! The nicest cage is twice as much as I paid for my car...
I had to google half of what you said, though...