suspension pickups on a main hoop?

Hello all.

Let's say your car was short and narrow like my old beetle, and you build a rear multilink suspension for it with some links that run forward at each wheel.
Picture something like the Volvo or merkur guys do where they build a box in the floor with a mount at the front and this longish trailing arm is bolted in to create a 4 link for a live axle car.

All this is legit in the rules and such and been done before.

On my beetle, I need to place the main hoop back a bit and could conceivably end up with the main hoop and the forward suspension pickups in about the same location... so I could just weld the pickups to the hoop for an upper and lower link on each side. I'm thinking a pair of plates with a bunch of holes for adjustment, like the circle track guys use, on each lower vertical of the main hoop.

for safety I'd probably offset the mounts a bit and weld a plate in to encourage the link to go outboard in a hard backwards impact so it didn't come towards an occupant.

Probably a NASA logbook, want to be RA legal too.

Legal? not legal? stupid idea? what say you.

The issues I see are:
1) is this becoming a tube chassis car with a body instead of "production based"
2) Someone may be concerned that main hoop integrity would be affected by the loading in a very serious accident. I think at the lower end it's braced a bunch anyhow by the door bars and the susp links would pull off before actually moving things around.

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Perry

FE570s course bike
KTM 950 ADV
74 Beetle turbo-efi etc..
72 Beetle stage rally project WRX powered
Attended about 15 rallies, usually a volunteer in a course car.

Nuthin huh? I expected at least a catchy slap down or maybe at best contact with an actual scrutineer, but nuthin?

I suppose I'll plan for the safe route, which is to install the mount an inch or two behind the hoop and tab it to the hoop as a "main hoop support attachment to the shell"..

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Perry

FE570s course bike
KTM 950 ADV
74 Beetle turbo-efi etc..
72 Beetle stage rally project WRX powered
Attended about 15 rallies, usually a volunteer in a course car.

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Perry
Nuthin huh? I expected at least a catchy slap down or maybe at best contact with an actual scrutineer, but nuthin?

I suppose I'll plan for the safe route, which is to install the mount an inch or two behind the hoop and tab it to the hoop as a "main hoop support attachment to the shell"..

Myself been busy.. I cannot imagine any problems running a E/W bar between the feet of the main hoop and picking up mounts off of that if I understand whatchoo are saying.. Maybe piccies drawings would help..

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John Vanlandingham
Sleezattle, WA, USA

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john vanlandingham

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Perry
Nuthin huh? I expected at least a catchy slap down or maybe at best contact with an actual scrutineer, but nuthin?

I suppose I'll plan for the safe route, which is to install the mount an inch or two behind the hoop and tab it to the hoop as a "main hoop support attachment to the shell"..

Myself been busy.. I cannot imagine any problems running a E/W bar between the feet of the main hoop and picking up mounts off of that if I understand whatchoo are saying.. Maybe piccies drawings would help..

The Mazda RX-3 that Michel Hoche-Mong now owns is done exactly this way.

Thank you sir.

The more I look, I suppose that almost anything goes in the open class as long as you don't put a sharp spike on the steering wheel.

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Perry

FE570s course bike
KTM 950 ADV
74 Beetle turbo-efi etc..
72 Beetle stage rally project WRX powered
Attended about 15 rallies, usually a volunteer in a course car.

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john vanlandingham
I cannot imagine any problems running a E/W bar between the feet of the main hoop and picking up mounts off of that if I understand whatchoo are saying...

Ain't none. There you go - an official scrutineery OK.

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Doivi Clarkinen
The Mazda RX-3 that Michel Hoche-Mong now owns is done exactly this way.

Yep. And that will be preserved, although I might change the links at both ends to Heims, depending on how much it binds when I get it all back together. We'll see. They may be far enough outboard that it's not a problem.

FWIW, the lower/outer front links just go to the stock brackets where the leaf springs went. They weren't reinforced. The car a hit (well, probably several) on the passenger side and the bracket held up fine, but the floor pan where it's attached buckled. It's tilted a degree or two. Summary: I think think leaf-spring brackets are pretty strong, but you may want to reinforce the area around them.

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Self-righteous douche canoe

Sorry all, I hassled you and then got super busy and ignored my own thread for a while..
I mean the suspension brackets/pickups are actually on the verticals of the main hoop. In the cheesy pic attached, the black is the approximate (measured with a micrometer of course) main hoop location and the yellow is two links of a 5 link independent rear suspension. We're talking about the pickups at the front of those links. Because the cabin of these cars is so narrow and the wheels stick out of the body, these links don't land on a bar that goes across the car, they end up right on the vertical lower part of the main hoop.

Hope this makes sense.

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Perry

FE570s course bike
KTM 950 ADV
74 Beetle turbo-efi etc..
72 Beetle stage rally project WRX powered
Attended about 15 rallies, usually a volunteer in a course car.

i favor a proper class 11 cage, check this out
http://www.thesamba.com/vw/forum/viewtopic.php?p=1819233

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I would rather drive a slow car fast as a fast car slow!
first rule of cars: get what makes you happy, your the one paying for it!