Recent Rollcage Rules Changes/Updates

[Greg Amy]

Though you should have seen these already, I just wanted to bring to your attention two recent rollcage rule changes/clarifications.

May 2010 Fastrack:

In 9.4.G.6, first sentence, delete “minimum”.

Background: during the 2008 GCR rollcage rules consolidation, the word "minimum" was added to the prior IT/SM/SS rules. This change effectively banned additional front leg tubes to the legal forward mounting pad. This was changed in the May Fastrack via Errors and Omissions.

May 5, 2010 email from SCCA Technical:

3. Cars competing in Improved Touring, Showroom Stock, Spec Miata, and Touring may extend one tube, from each front down tube, forward to the firewall, bulkhead or wheel well, but not penetrating [strike]the firewall[/strike] any panel.

I do not know the background on this one. It appears to be an offshoot from an issue years ago where Spec Miata guys were mounting their front legs on the inner fender panel, not the true "firewall" at the front. I do not see where this would affect existing cages, it only seems to allow alternate mounting locations for these front legs.

I also do not see where this is a conflict with the allowance from the May Fastrack, as this allowance is an optional tube as well. However, I recognize that us "intorturators" may mis-interpret the "one tube" to be in conflict; I suggest the Fastrack allowance illustrates it's not intended to be so.

GA

 

[ddewhurst]

Here is another winner.



DATE: March 20, 2010
NUMBER: TB 10-04
FROM: Club Racing Board
TO: Competitors, Stewards, and Scrutineers
SUBJECT: Errors and Omissions, Competition Adjustments, Clarifications, and Classifications
All changes are effective 3/1/10 unless otherwise noted.

GCR
1. #706 (CR Clarify side protection tubes attachment
In GCR 9.4.D, add a new second sentence: “Tubes that are welded to any part of the same mounting plate are considered
to be connected to one another (see 9.4.E.3 below).” [This confirms Racing Memo 10-02.]

 

[Greg Amy]

Good catch, David. I know the background on that one, too.

It's basically due to Miatas that mount the main hoop on top of the solid rear deck shelf (a strong part of the chassis) then extend the mounting plates down the side so they can get the door bars (which are required to attach to the main hoop) at hip and mid-torso level. Done correctly, it's quite safe (Kessler built one for me like that) and it allows the main roll hoop to be in a better position for a taller driver (I'm 6'1" and fit easily with a cage like that.)

GA

 

[JoshS]

Good catch, David. I know the background on that one, too.

It's basically due to Miatas that mount the main hoop on top of the solid rear deck shelf (a strong part of the chassis) then extend the mounting plates down the side so they can get the door bars (which are required to attach to the main hoop) at hip and mid-torso level.

Came out of here in SFR. We probably have 150+ Miatas built that way here, as well as a bunch of other cars like S2000s, and a tech steward got a little excited pre-season back in February with a new build. Letters were sent and calls were made and it was resolved very quickly.

 

[Flyinglizard]

The lower door bars will be weak due to the flex of the mounting plates. The door bars are to connect to the hoop. The hoop cross bars keep the door bars from moving.

 

[Marcus Miller]

The lower door bars will be weak due to the flex of the mounting plates. The door bars are to connect to the hoop. The hoop cross bars keep the door bars from moving.

I dare say 'most' SM's are built the way tGA described, and seeign as we know SM's hit anything and everything, any weakness from mounting to the mounting plate, not the main hoop it doesn't seem to be an actualy problem...

disclaimer: I'm currently having my 2nd personal Miata built, ~10th I've worked with and its using this architecture.

 

[Chip42]

mounting to a plate rather than a tube is certianly prone to felxing.

mounting that plate, in turn, to a solid portion of the chassis will make the flex go away. reinforcing the chassis with cross bracing (main hoop, main hoop corss braces, fornt hoop and corss barces, etc..) will help even more.

there's no reaosn that this style of build can't be perfectly safe if done well. I'd rather be in a miata with a cage like this than a 1st gen RX7 with the cage welded to 0.080" plates to a rusted out floor, flexing door bars or not.