Re: [alfa] Re: ROLL BARRED

[Richard Welty <rwelty@xxxxxxxxxxxxxxx>]

On Fri, 03 Oct 2003 13:51:43 -0400 SHartDP@domain.elided wrote:
> A properly built roll bar made out of good materials can be kept in the
> vehicle depending on the crash.  I've seen race trucks (desert race -
> not that roundy round BS) go over going about 80+ MPH go end over end
> multiple times in the dirt and be structurally fine.  There might be a
> tube or 2 that is bent or cracked and can be replaced, but many times it
> is not the case.

when tub based SCCA cars roll (on asphalt), i have been known to give them
the once over and approve them for continued competition the next day if i
don't see any problems.

>  These cages are often built out of 4130 chomoly
> though, and if not chomo then DOM (which is just a higher grade,
> seemless mild steel tube).
> Having seen an autopower cage up close (my unlce's got one in his 65 GT)
> it's pretty good for an off the shelf, bolt in roll bar.

Autopower has always made it a point to easily clear the basic SCCA
standards.

> One question I have though is why is ERW banned in SCCA now?  Has there
> been a history of people using hot rolled instead of cold rolled steel,
> or possibly bending the tube with the seam on the outside of the bend
> (making the seam prone to tearing)? 

mostly the latter, i think. Kurt Weiss (an engineer and cage builder who is
now chairman of the SCCA Competition Board) also feels that there are
significant strength advantages to DOM in general. i've not talked to him
about the exact reason for bagging ERW, but i'm sure that the case was
there for the ban (incidentally, Kurt built the cage in my currently stored
SCCA ITB Alfetta Sedan, to put some Alfa content back into this thread.
it's made from 1.75" 0.095 wall DOM, not suprisingly given that Kurt built
it.)

> It seems that a properly designed
> roll bar or cage made out of regualr seamed mild steel would be plenty
> strong for most of the SCCA stuff.

like i say, they probably had their reasons. perhaps i'll drop Kurt a line
and ask him about the exact reasoning.

richard
-- 
Richard Welty                                         rwelty@domain.elided
Averill Park Networking                                         518-573-7592
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