rollcage mounting area limitations?

[tom91ita]

The GCR states 144 sq. inches and no more than 15" per side and can be in multiple planes;

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 but shall not be greater than fifteen inches on any side.

Is this a maximum of 15" as layed out prior to cutting or bending to change planes?

my CRX has two "levels" where the main hoop are typically attached. The most obvious is the "floor" of the primary passenger compartment and the other is the bottom of the "shelf" area of the cargo area immediately behind where the seats mount.

i have seen bars mounted both ways but leg room is better in the style where the main hoop is back on the "shelf" section. however, i do not like the fact that my butt is not "inside" the cage as much on the "shelf" mounted style.

so if the 15" is measured on each plane (after bending the first flat piece), i can run a 3" wide mounting plate to the "floor" of the car and box in that corner and have the bottom rail of the cage from the front A-pillar bar hit that portion of the mounting plate even though it is below the main hoop.

so is this OK?

if this is not making any sense, i'll try to cut some white pieces of cardboard and put in the car and post up a phone pic to better illustrate.

tia, tom

[Knestis]

The common interpretation I've seen is that you cant exceed that area measurement for the entire area of the surface of the 'plate' in all of its planes. So if you had 100 sq in on the floor, 30 sq in running vertically up the rocker, and 10 sq in on top of the rocker, you'd be OK.

K

[ddewhurst]

***So if you had 100 sq in on the floor, 30 sq in running vertically up the rocker, and 10 sq in on top of the rocker, you'd be OK.***

Provided the accumulative length of those ^ three (3) seperate side planes didn't exceed fifteen (15) inches.

I have viewed some cars with the main hoop on the package shelf & it leaves me feeling a bit squemish. I get a giggle out of the words of the main hoop rules vs the pictures of the main hoop. All pictures of the main hoop obviously show the mainhoop & front hoop or side hoops are anchored to the floor. The words of the rule say nothing about the main hoop being anchored to the floor. At one time were words included that said the main hoop shall be anchored to the floor. I could care less about the 1 in 1,000 drivers that are 6' 6" that weight 360 pounds.

[raffaelli]

At 6'4 300lbs, and the main hoop down on the floor in my CRX, I am a bit snug for leg room. We did consider it up on the shelf but for the two items listed above - butt below the cage, and rules show it on the floor, we out the hoop and plate on the floor.

[Speed Raycer]

Tom, pics will do wonders. Depends on the structure in the area that you're planning on mounting to.

David, I think we can all agree that on most chassis', the "floor" is not the best place to mount a main hoop regardless of generic pics that are used to illustrate typical cages in everything from a SM to a GT car. In a SM there is WAY more structure on the package shelf than the floor. I've mounted both to the "floor" and to the package and it's really case dependant. That 6'6" driver needs the hoop mounted to the package shelf so that their helmet isn't under the main hoop (which IIRC is one of your favorite issues correct??? ). That 5'2", 120lb driver has enough room to mount the thing at the lower factory seat belt anchors!

IMO, when laid out flat, the pad cannot exceed 15" on any side/edge. So ignoring the square inch rule for a minute, I can have a 5 sided pad (pentagon) with each side being 15" long. Angles are your friend when it comes to maximizing your pad area.

[ddewhurst]

***I think we can all agree that on most chassis', the "floor" is not the best place to mount a main hoop***

No, I'll take my three sided boxed floor/rocker panel/lower vertival package shelf wall.

***In a SM there is WAY more structure on the package shelf than the floor.***

In your humble judgement. I have no facts to back a statement like that ^ up.

***regardless of generic pics that are used to illustrate typical cages in everything from a SM to a GT car.***

I believe a protest of a package shelf mounted main hoop would be found illegal because IMHJ the pictures are an equal part of the GCR rules as the words are. There is nothing within the words that trumps the pictures of the floor mounted main hoop.

***That 6'6" driver needs the hoop mounted to the package shelf so that their helmet isn't under the main hoop (which IIRC is one of your favorite issues correct??? ).***

I'm 100% in agreement the driver belongs within the five planes of the roll cage with the floor being the sixth plane. Package shelf mounted main hoop, not. IIRC there is a Spec Miata from Iowa that received a notation in his log book with reference to his package shelf mounted main hoop. I need to see him at the track & see how he resolved the log book issue.

Had the 600 not been rain delayed again I wouldn't have had time to get back to the pc.

[Flyinglizard]

The "official" notes from SCCA , is that the pics are for reference, "the words are the rule." (J Baurer)?
I sent a note about my SM , with crossed main hoop braces. They are at least as strong as the straight braces and make a lot more sense for the Miata, passing through a better part of the rear wall, not through the trunk hinge area. "Many recent builds have crossed rear bar braces."
The floor only mounts are by far the weakest(especially if welded 360*), the rocker box/floor/sill is the best.
The pics are just suggestions. MM