I have a Cage in may car made from DOM steel tubing I want to add some braces and was wondering, if i can use Chrome moley tubing for the extra braces or i would need to get some more heavy DOM tubing? Thanx in advance

 

SCCA requires that you use the same size tubing, whether you use chome-moly or DOM. Chome-moly and DOM that is the same dimensions, weighs the same.

 

If you are adding extra tubes that are not required, say, adding a cross brace between 2 points already existing in the car, you can use anything you like. If you are adding bars that are required, you will have to the same size and thickness the main hoop is.

The GCR is a pretty decent rule book. It says that all tube that is required can be no less than what is specified, you can add more if you like, as long as you do not exceed the 8pt rule! main hoop (2), A-pillar, forward hoop (2), rear support to main hoop (2), and 6 and 7 to front bulkhead.

It says you can add as many additional bars(kind of) as you like, as long as you mount them to your 8pts or any where in the main cage structure. My local TECH says I can you any size tubing I deem safe. The cage needs to follow some sort of form as shown in the GCR. It also tells you if you cannot follow that form, You need to get an certified Engineer to draw up your proposal, send it to SCCA, and have them study it and OK it. Very expensive and time consuming. That allows SCCA to put the blame on the engineer, not them.

You will never go wrong by calling your local SCCA or Conference Tech! They will let you what is legal.

Myself, being a Race car Fabricator, I would not recommend using chrome moly tubing in an 1020 DOM cage. The materials have different strengths and weaknesses. Safe way is to keep it all the same. think about the forces applied to the cage and which bar you are adding. Is the tube in tension or compression? Stuff like that.

Roll cage prep and manufacturing is a serious job. It Roll cage has to allow the uni-body some sort of collaspe to absorb energy and still keep its shape around the driver's area. It can also be used to stiffen the suspension pts and make the interior structure safer. Sometime adding more bars will creates an adverse condition. I Hope that doesn't confuses you even more!

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by raceruss &raquo;</TD></TR><TR><TD CLASS="quote">If you are adding extra tubes that are not required, say, adding a cross brace between 2 points already existing in the car, you can use anything you like. If you are adding bars that are required, you will have to the same size and thickness the main hoop is.</TD></TR></TABLE>

I believe even non-required bars must meet the minimum tubing size.

 

The car has a complete 8 point DOM cage that meets SCCA and all other requirements. Now the car is going so fast it even scares me. The new tubes will be for stiffness and safety.

 

Page 135, 2003 GCR, paragraph 18-1, sub para 6, states all required cage elements be of same dimension.

Page 148, 2003 GCR, Section 18.5 touring roll cage, paragraph 2 states the same. All required tube, same dimension.

If addition tubes were to be same, it would state that also, example Gussets. No rule on what size, can be plate, or tube, What size?

As I said before, check with your regional tech!

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by raceruss &raquo;</TD></TR><TR><TD CLASS="quote">
If addition tubes were to be same, it would state that also</TD></TR></TABLE>

Maybe this was a 2003 rules change, as I am looking at a 2002 which states:

"Any number of additional reinforcing bars are permitted within the structure of the cage, provided they meed the minimum tubing size per GCR Sections 18.1.6.C"

Did they change this language in 2003? Dang, I guess I do need to buy the new book. Maybe I'll wait until '04.

 

Rule changed was 1-1-03

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by raceruss &raquo;</TD></TR><TR><TD CLASS="quote">Rule changed was 1-1-03</TD></TR></TABLE>

*closes his rulebook, quietly walks away*

Thanks for the update

 

*kicks travis in the *** on the way out*

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by travis &raquo;</TD></TR><TR><TD CLASS="quote">

I believe even non-required bars must meet the minimum tubing size.</TD></TR></TABLE>

I'm sure this has been discussed already, but how dumb a rule is this? It seems like they are discouraging those with weight-disadvantaged cars from adding more reinforcement. Even thin-wall tubing is better than nothing at all...

 

If we are dealing with IT cages, which I believe the majority of this board deals with, then the tubing sizes must be identical throughout the cage as previously stated.

The 2003 GCR, Section 17.1.4.D.10.a.5, page 21 of the ITCS states:

"Any number of additional reinforcing bars are permitted within the structure of the cage, provided they meed the minimum tubing size per GCR Sections 18.1.6.C"

I cannot find any verbage within the Fastrack's changing this requirement:

Jan Fastrack link: http://www.scca.org/news/fastrack/03-01.pdf

Correct me if I missed it somewhere. Here's the link to all fastracks
http://www.scca.org/news/tech/....html

Travis, don't turn tail so quickly. You can hold your head up here.

Rick

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by turfer &raquo;</TD></TR><TR><TD CLASS="quote">
Travis, don't turn tail so quickly. You can hold your head up here.
</TD></TR></TABLE>

LOL! I'm standing on shaky ground with my 2002 GCR. If you can keep RJ from kicking me in the ***, by all means, help a guy out!

 

Yes, The rule has changed. It was that all the tubing in the cage had to be the same size, now it says that all the tubing has to meet the mininum spec for the car weight.
I don't know how the little gusset tubes are viewed, but they look like little punches to me. I think that the original ones, on some of the rally cars, where pieces of formed tubing that started at say 1 1/2", squeezed down to 1", then back to 1 1/2" . This keeps them from weaking the tube that they are welded too, because it wraps around the tube as a proper fish mouth should. NASCAR uses pieces of of thin wall tubing to hang the bodies with, and you would be amazed at the damage they can do to a piece of .095 wall tubing.