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Steel VS Cromoly rollbar?

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Old 01-15-2009 | 08:40 AM
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Default Steel VS Cromoly rollbar?

I picked up a used Wolfe 6pt rollbar at a good price this winter.
I have not installed it yet, I'm starting to wonder if maybe Cromoly would have been a wiser choice.

So $685 for a new rollbar (weld-in, jig notched, over the seat + shipping)
Looks like a difference of 45lbs (85 VS 130)
45lbs is significant; but then again, my car is a pig anyhow.
I could probably get $200 out of the old bar if I sold it.

Thoughts?
Old 01-15-2009 | 08:43 AM
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I don't hear of ANYONE using mild steel, almost everything is Chromoly since its adds so much weight to begin with, most people who race want that penalty to be as low as possible.
Old 01-15-2009 | 09:14 AM
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A lot of people use mild steel. I don't because I'm concerned about weight, and tig welding looks so much nicer. Some don't think it is worth the cost difference, some do. A lot of cars come through here with mild steel roll bars.
Old 01-15-2009 | 09:47 AM
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I don't think there is that much weight difference in a 6pt bar set-up unless the MS tube wall was overly thick.

Bird in hand, its there use it.

I went to school for physics and honestly MS is the better material to use in pretty much anything over 2700lbs. There is a reason why every major sanctioning body that deals with door-style cars do not allow chromoly to be used in the rollcage portion of the cars. Chromoly is brittle compared to MS and when you weld chromoly it becomes even more brittle. Chromoly is very difficult to weld correctly as well.

If you ever get to inspect a bad accident involving a chromoly car you will see lots of broken tubing generally before or after the welds, whereas if you look at a nascar wreck all you see is bent tubing.
Old 01-15-2009 | 09:51 AM
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IIRC CM is about 30% lighter based on wall thicknesses.
Old 01-15-2009 | 10:06 AM
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Added advantage, my MS bar doesn't have swing-outs.
If I ordered a CM rollbar, I'd add that option for $170.

I do drive this car on the street quite a bit.
Old 01-15-2009 | 01:48 PM
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Originally Posted by tomcowle
There is a reason why every major sanctioning body that deals with door-style cars do not allow chromoly to be used in the rollcage portion of the cars.
I think your mistaken. NHRA does allow cm for roll cages. My SS car is certified to go 8.50, most of my friends have full cages and are certified to 7.50, those are also NHRA Super Stock and Comp Eliminator cars. Pro Stockers are cm also, but only have to weigh about 2350. All full cm tubing. Tig welded and anealed properly, there are no problems.
Old 01-15-2009 | 02:24 PM
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Originally Posted by Ed Wright
I think your mistaken. NHRA does allow cm for roll cages. My SS car is certified to go 8.50, most of my friends have full cages and are certified to 7.50, those are also NHRA Super Stock and Comp Eliminator cars. Pro Stockers are cm also, but only have to weigh about 2350. All full cm tubing. Tig welded and anealed properly, there are no problems.
actually...to go faster than 7.50 (25.2 spec) MUST be constructed of chromemoly. mild steel cages will only certify to 7.50
Old 01-15-2009 | 02:55 PM
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i just bit the bullet and installed a 10pt chromoly. Yes it cost a few hundred more, and yes my car was already a pig..almost 3900 lbs. I figured i should cut weight where i could and not regret it later. IMO buy a choromoly.

45lbs seems like a lot, maybe a 10pt? 6pt difference i dont think is that much?
Old 01-15-2009 | 02:58 PM
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Originally Posted by Fireball
actually...to go faster than 7.50 (25.2 spec) MUST be constructed of chromemoly. mild steel cages will only certify to 7.50
There ya go.
Old 01-15-2009 | 04:19 PM
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Ed I meant to type other than NHRA/IHRA drag racing.

SFI Foundation gets their chromoly destructive testing info from the airplane industry thats directly related to drag racing right??

Chromoly does have its place in the drag racing world and I'm sure nothing I say or type will change that however I've done the math and seen the results first hand on the heavier stuff and the lost the life of a good guy/friend (Ian Landies Sr.) with improperly welded CM by a supposid professional chassis shop.

James Montigny, why can't you add swing outs to your mildsteel bar? Plenty of bars have been retro-fitted with swingouts
Old 01-15-2009 | 04:38 PM
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I just had a Wolfe CM 6 point installed and it weighed in at under 65lbs out of the car. I got the Wolfe swingouts but I would advise against that, they are very intrusive at the pivot, look like crap, and use small pins. My fabricator later told me he uses Chris Alston swingouts and I would have much rather had them. If I were you I would try to find a semi local shop with a good rep to do a custom install. It will fit alot better and probably won't cost much more, if any at all.

Larry
Old 01-15-2009 | 05:51 PM
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I just got a wolfe 6point notched cromoly and the shipping "bundle" is 57.77#s

I have a wolfe bolt in MS. thats I'll weight if I get a chance. But just a box I put all the 3/8th plate bolts/washers/nuts,(24 of them) and the 4 big 1/2 bar hardware, and the under floor 1/8 6x6 plates. That box is like 12-15#s right there.
Old 01-15-2009 | 05:57 PM
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For just the six point I couldn't justify spending the extra money for the slight savings in weight. I could find that weight elsewhere in the car for free.
Old 01-15-2009 | 07:47 PM
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Its weight youll never be able to take out....
Old 01-15-2009 | 08:55 PM
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Originally Posted by nahasapeemapetalon
45lbs seems like a lot, maybe a 10pt? 6pt difference i dont think is that much?
That's based on the info on Wolfe's site for 6pt
I have nothing to confirm or argue those numbers.
I shouldn't need a 10pt anytime soon. I'm looking at low 11s N/A
Although, you never know what the next season will bring

Originally Posted by tomcowle
James Montigny, why can't you add swing outs to your mildsteel bar? Plenty of bars have been retro-fitted with swingouts
That's true, I could have it done. I hadn't thought about that.

Originally Posted by VIPRETR2
I just had a Wolfe CM 6 point installed and it weighed in at under 65lbs out of the car. I got the Wolfe swingouts but I would advise against that, they are very intrusive at the pivot, look like crap, and use small pins. My fabricator later told me he uses Chris Alston swingouts and I would have much rather had them. If I were you I would try to find a semi local shop with a good rep to do a custom install. It will fit alot better and probably won't cost much more, if any at all.

Larry
Thanks Larry, good and advice and you read my mind.

I talked to the gentleman who sold me the rollbar (and who would be installing it) today and
he said he could fab me up a CM rollbar, so that makes the decision much easier.
I'll have to prod him for a price and timeline when I get the car back from being tuned this month.

Originally Posted by nahasapeemapetalon
Its weight youll never be able to take out....
Or rather that it would be difficult to remove, yes.
Old 01-15-2009 | 09:13 PM
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Originally Posted by Fireball
actually...to go faster than 7.50 (25.2 spec) MUST be constructed of chromemoly. mild steel cages will only certify to 7.50
and 25.5 cars can be made with mild steel but they are not worth any money, may to much weight.

I would go molly, if you sell the car or ever want to upgrade you can allways add on with the molly but past a 10 point I don't know anyone that would add on a 25.X to a 10 point, they pretty much allways want to cut them out and start over.

My notched molly WOLFE 10 point for my last car had a shipping weight of like 72 pounds and I really think the mounting plates weighed a good 20 pounds
Old 01-15-2009 | 09:24 PM
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Originally Posted by JUICED96Z
I don't know anyone that would add on a 25.X to a 10 point, they pretty much allways want to cut them out and start over.
Yeah, I really don't see me doing a 25.X in my hawk.
At that point, I'd just buy a rolling chassis I didn't have any emotional
attachment to and start hacking away at it.
Old 01-15-2009 | 11:48 PM
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From what I understand a CM 6 point is about 20 pounds lighter than a ms 6 point
Old 01-16-2009 | 06:55 AM
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ill be puttin in a 10pt soon and we'll probably be goin with a MS cage just because the money but id love to save the weight with CM. ill probably be usin a chris alston kit that doesnt go through the dash. if i could afford it id use the CM so if you have the money do it.


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