Roll cage: anyone install?

[apecush]

Originally Posted by Richard@M-World

1. I would only go for a cage using chromoly because it is a much stronger material than mild steel. More expensive but worth the money IMO.

The organizations local to me have pretty much outlawed anything other than mild steel. The problem here is that too few people know how to properly weld steel with a high CE. You need careful preheat and interpass control, and you need to post weld heat treat, or else you end up with welds that look nice but are either cracked or have zero toughness. While chromoly is stronger than mild, it won't be any stiffer for an identically designed cage.

[s65e90]

Originally Posted by apecush

The organizations local to me have pretty much outlawed anything other than mild steel. The problem here is that too few people know how to properly weld steel with a high CE. You need careful preheat and interpass control, and you need to post weld heat treat, or else you end up with welds that look nice but are either cracked or have zero toughness. While chromoly is stronger than mild, it won't be any stiffer for an identically designed cage.

chromoly is much lighter than a full mild steel cage. Your post scares me kinda knowing that they only allow mild steel cages???

[apecush]

I just re-read the regulations, chromoly is allowed, but is strongly discouraged. If you have a welding engineer draft you a procedure for chromoly, and the cage is welded/nondestructively inspected accordingly, go nuts. Otherwise, is getting crushed/impaled by the cage in a rollover worth the weight savings? As a metallurgical engineer, I certainly know where I sit on the subject.

FYI, don't expect pay less than $10k for an appropriately qualified procedure.

[s65e90]

Originally Posted by apecush

I just re-read the regulations, chromoly is allowed, but is strongly discouraged. If you have a welding engineer draft you a procedure for chromoly, and the cage is welded/nondestructively inspected accordingly, go nuts. Otherwise, is getting crushed/impaled by the cage in a rollover worth the weight savings? As a metallurgical engineer, I certainly know where I sit on the subject.

FYI, don't expect pay less than $10k for an appropriately qualified procedure.

Chromoly cages are used everywhere in some of the fastest cars around. 10k? Where do you live? I could get a nice 10 pt in chromoly for much, much less. Your prices are approaching 25.2 dragster stuff

[leo95se]

Has anyone installed an autopower cage?

[apecush]

Originally Posted by s65e90

Chromoly cages are used everywhere in some of the fastest cars around. 10k? Where do you live? I could get a nice 10 pt in chromoly for much, much less. Your prices are approaching 25.2 dragster stuff

10k for a welding procedure to weld in a cage, not the cage itself. I'm sure there are professional race shops out there that have the appropriate procedures and controls to manufacture the cages. Chances are; however, that the local independant shop that makes 3 cages a year doesn't (which is the norm around my area).

[surlynkid]

Originally Posted by apecush

10k for a welding procedure to weld in a cage, not the cage itself. I'm sure there are professional race shops out there that have the appropriate procedures and controls to manufacture the cages. Chances are; however, that the local independant shop that makes 3 cages a year doesn't (which is the norm around my area).

who would take their car to a shop for a cage if they only built 3/year. the only good way to build a cage is chromoly DOM tube. beyond race cars, all the rock crawlers and buggies are building them this way. there are a ton of qualifed shops, but perhaps none by you. nobody should be using mild steel. give me a fully tig welded chromoly. it certainly is not $12K either.

[apecush]

[QUOTE=surlynkid;14041640]nobody should be using mild steel.QUOTE]

That is a dangerous comment. Care to share your logic?

For a tube of identical strength, a mild steel one will be approximately 36% heavier. It will also be 36% stiffer, and FAR easier to shape and weld.

edit: i'm going to stop mentioning welding procedures and their associated cost because it is pretty clear that nobody understands their relevance to a safe chromoly cage.

[1MOREMOD]

I used bamboo and duct tape. Is that okay?

[apecush]

Originally Posted by 1MOREMOD

I used bamboo and duct tape. Is that okay?

"green" cage? I think you're on to something for the prius race crowd (or is that an oxymoron?)

[1MOREMOD]

Originally Posted by apecush

"green" cage? I think you're on to something for the prius race crowd (or is that an oxymoron?)

They raced the prius against the m3! My problem is panda bears keep trying to eat my interior.

[surlynkid]

[QUOTE=apecush;14042407]

Originally Posted by surlynkid

nobody should be using mild steel.QUOTE]

That is a dangerous comment. Care to share your logic?

For a tube of identical strength, a mild steel one will be approximately 36% heavier. It will also be 36% stiffer, and FAR easier to shape and weld.

edit: i'm going to stop mentioning welding procedures and their associated cost because it is pretty clear that nobody understands their relevance to a safe chromoly cage.

I know all about welding procedures. Should I add up all the 1,500 psi ethylene piping we have at my plant. My last plant had 30,000 psi ethylene lines. We kind of pay a little bit of attention to that.

You are apparently too stuck on easier and cheaper. Weight is important. A properly designed cage in chromoly is plenty safe.

[Endless619]

Originally Posted by 1MOREMOD

If you are wearing a harness your not going to end up in the back seat. Problem comes more with full cage than half.

Agreed.

I would go with a half cage. I had a full rollcage with my Hondas and it was very unsafe for street driving unless I had a helmet. Your head in a rollover would be on the bar or smashed against it.

[1MOREMOD]

Originally Posted by Endless619

Agreed.

I would go with a half cage. I had a full rollcage with my Hondas and it was very unsafe for street driving unless I had a helmet. Your head in a rollover would be on the bar or smashed against it.

You could always wear a helmet on the street and see how that goes over?

[apecush]

[QUOTE=surlynkid;14043152]

Originally Posted by apecush

You are apparently too stuck on easier and cheaper. Weight is important. A properly designed cage in chromoly is plenty safe.

not stuck on easier/cheaper, stuck on the fact that so many people that think they know what they are doing fuck these things up. I agree 100% that a properly designed/manufactured cro-mo cage is safe.

[bigjae1976]

I've done quite a bit of research on this. I'd either go full weld in cage or a simple 4pt bolt in. I think a welded in 4pt leads to regret further down the road. PM Thundermoose.

For my E46, I'm going 4pt bolt in. Not really wanting to trailer it everywhere at this point.

Either way, you can install ample padding on the bars which can provide good protection for your dome piece.

[leo95se]

Originally Posted by bigjae1976

I've done quite a bit of research on this. I'd either go full weld in cage or a simple 4pt bolt in. I think a welded in 4pt leads to regret further down the road. PM Thundermoose.

For my E46, I'm going 4pt bolt in. Not really wanting to trailer it everywhere at this point.

Either way, you can install ample padding on the bars which can provide good protection for your dome piece.

I agree. Now I just need to find a bar.

[bigjae1976]

Originally Posted by leo95se

I agree. Now I just need to find a bar.

You're welcome...

[1MOREMOD]

Originally Posted by bigjae1976

I've done quite a bit of research on this. I'd either go full weld in cage or a simple 4pt bolt in. I think a welded in 4pt leads to regret further down the road. PM Thundermoose.

For my E46, I'm going 4pt bolt in. Not really wanting to trailer it everywhere at this point.

Either way, you can install ample padding on the bars which can provide good protection for your dome piece.

i may regret not following this advice if full cage enters into my future. im welded in rear cage.

[leo95se]

Originally Posted by bigjae1976

You're welcome...

Nice. Headed to my workshop now. Ill even use lap joints for added strength.