new cage rules

[dickita15]

So I have been looking over the new cage rules and I think I see some unintended consequences. The new attachment point rules limit the plates to 144 sq. in. but there would no longer be a 12” maximum length on any one side. We have learned from the past that that any number of tubes on one plate is one attachment point. Is there anything that prevents someone from using plates that are 4” x 36” for each of the eight attachment points and use as many tubes as you want? It is not much of a stretch to have a full GT cage. Thoughts?

E. ROLL CAGE ATTACHING POINTS
A. AMERICAN SEDAN, IMPROVED TOURING, SHOWROOM STOCK, SPEC MIATA, AND TOURING CLASSES –
The roll cage must attach to the vehicle structure (floor pan/ rocker boxes) within the passenger compartment in
a minimum of six points and a maximum of eight points as specified in these rules.
B. All other classes – There is no limit on cage attachment points. The roll cage shall be integrated into the
frame or chassis.
C. Mounting Plates
a. Mounting plates welded to the structure of the car shall not be less than .080 inches thick. The maximum
area of each mounting plate in the American Sedan, Improved Touring, Showroom Stock, Spec Miata, and
Touring classes shall be 144 square inches. Plates may be on multiple planes.
b. The thickness of mounting plates bolted or riveted to the structure of the car must not be less than the
thickness of the roll hoop or brace that they attach to the chassis, and must be backed up with a plate of equal
size and thickness on the opposite side of the chassis panel. The maximum area of each mounting plate must
be 144 square inches. Plates may be on multiple planes.

[Knestis]

An excellent question, Dick! Well done.

I think the answer is, "yes - you can do pretty much whatever you want," so in terms of cage design there probably will be some unintended consequences.

However, I'm not tempted to believe that that kind of construction is going to translate into dramatic improvements in competitiveness, if pushed to the limit - particularly as OE unibody construction has gotten better over the years...

...with the possible exception of leveraging this change as an opportunity to better resolve loads from the rear suspension. There could well be dividends to be paid there, and probably more for some cars than others, but designs will be hobbled by the limitation (assumption?) that tubes stay inside the passenger compartment in back.

K

[Gary L]

...with the possible exception of leveraging this change as an opportunity to better resolve loads from the rear suspension. There could well be dividends to be paid there, and probably more for some cars than others, but designs will be hobbled by the limitation (assumption?) that tubes stay inside the passenger compartment in back.

K [/b] Not sure I understand your assumption... there is a limitation, but it's not the passenger compartment that defines the boundaries. Under the proposed rules, the main hoop braces can go as far aft as the rear shock towers, and any number of additional tube elements are permitted within the boundaries of the minimum cage structure.

Having said that, the new rule (with rearward limitation at the shock towers) is actually more stringent than the current allowance. :blink:

[Greg Amy]

Is there anything that prevents someone from using plates that are 4” x 36” for each of the eight attachment points and use as many tubes as you want?[/b]
No. In fact, that's the reason the 12" rule was implemented in, what?, 1995? Guys were welding in extremely thick plates all along the rocker panels and other key areas, strengthening up the flexi-chassis.

What's old is new again...

[Bill Miller]

:026: WHEE!!!!!

[seckerich]

Saw that and missed the deletion of the single side restriction. Now you could weld the full length of the door opening and run the front pads all the way up the A pillar. I think that needs to be addressed or I must agree with Bill on this one. :026: Quick--cut the cage up before they come to their senses.

On Edit--Just spoke to Jeremy at SCCA and he said this is a starting point and they would like these loopholes pointed out and letters for and against would be good. This rule would make every IT cage obsolete in most respects so I will be writing to ask that the single side rules carry forward with a small increase in the length (maybe 15" max) to stop the full WC cage builds.

[Knestis]

Not sure I understand your assumption... there is a limitation, but it's not the passenger compartment that defines the boundaries. Under the proposed rules, the main hoop braces can go as far aft as the rear shock towers, and any number of additional tube elements are permitted within the boundaries of the minimum cage structure. ...
[/b]

From Dick's original post:

A. AMERICAN SEDAN, IMPROVED TOURING, SHOWROOM STOCK, SPEC MIATA, AND TOURING CLASSES –
The roll cage must attach to the vehicle structure (floor pan/ rocker boxes) within the passenger compartment in a minimum of six points and a maximum of eight points as specified in these rules.

Hmmm... Not parsing the new text word-by-word but...?

K

[Gary L]

From Dick's original post:

A. AMERICAN SEDAN, IMPROVED TOURING, SHOWROOM STOCK, SPEC MIATA, AND TOURING CLASSES –
The roll cage must attach to the vehicle structure (floor pan/ rocker boxes) within the passenger compartment in a minimum of six points and a maximum of eight points as specified in these rules.

Hmmm... Not parsing the new text word-by-word but...?

K [/b]

The "...as specified...." part tells me you can go all the way to the rear shock towers. I think. :D

[Ron]

Do I also read that factory door bar things can be removed if you have NASCAR door bars. I only read it once quickly. Of course I just built a new cage this year to the old specs in the Mustang.

[Chris Wire]

Letter sent.

Maximum 15" length of any given side seems reasonable.

Good call.

[Speed Raycer]

:P Typical racers... they've given you 12" for years and now you want 15!!! :P

For me, 12" is plenty. I think I've only had a couple of pads that I even got close to 12" in a straight line. But, now that they're giving me 44 more square inches to work with, 15 might be a good number :D

[shwah]

I don't think I would build my cage much different today with that wording. Just because it says you can, doesn't mean it makes a difference.

[joeg]

Solves some jacking point issues I suppose...

[Bill Miller]

I don't think I would build my cage much different today with that wording. Just because it says you can, doesn't mean it makes a difference.
[/b]


Chris,

The whole reason they put the 100 sq. in. and 2"/12" limitations in, was because it DID make a difference.

Did I say WHEEE! yet? :026:

[Eric Parham]

Since the pre-95(?) logbooked cars have unlimited mounting plates (no 100 sq in or 12 in side limitations), I don't think any 12" or 15" limitation should apply to the new rule. Many folks still run old cars for that perceived advantage. We'd now be limited by the rear shock towers and the front firewall. Seems good enough (and perhaps better) to me :)

Question on the new doorbar rule: How close to the passenger door does the 2nd bar have to be? I haven't run this year (basically taking the year off but wouldn't mind running last year's car a couple of times to keep the old license current). In my more current old car, I have one regular doorbar, plus two (or more) bars that come from the center of the cage to the RF downtube. Can these be considered doorbars since they are between the driver and the door? They look just like standard doorbars from a side view.

[lateapex911]

Doubtful...I'd imagine tech will insist that a doorbar start on the RF downtube and end on the roolbar. The GCR states this as well.

[shwah]

Chris,

The whole reason they put the 100 sq. in. and 2"/12" limitations in, was because it DID make a difference.

Did I say WHEEE! yet? :026:
[/b]

Is there data to support this? I have not been deeply involved in IT long enough to know. I still don't see enough benefit for the effort to justify redoing my 1 yr old cage. Othere places like more seat time, radios and data aquisition will yeild more improvement for me personally.

[ddewhurst]

***Is there data to support this?***

I'm with Bill. Dam, did I really say that. :o

[Bill Miller]

***Is there data to support this?***

I'm with Bill. Dam, did I really say that. :o
[/b]

Killed ya didn't it! :D

Thanks for the note, go see those guys play, it's awesome.