some good roll cage buidling guides

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Do It Sidewayz
I really like doing about what the above pictured is....

but instead i like using a "TUBE Gusset", on the windshield side of the junction, which goes to the center line of the "roof bars", then attaching the "A pillar support" bars to where this Tube gusset intersects the half laterals (the allowable 4" down from the top of the windshield)

I like it because it lets you move the a-pillar support bars forward the allowed 4", and not just have them "dead end" in the middle of the tube. It gussets the windshield area a bit. and also creates a nice load path all the way from the bottom of the a pillar, up the support tube, through the gusset tube, through the roof v-bars, to the main hoop, and down to the rear stays/strut towers......i like nice load paths to disperce energy, I don't like dead ended tubes in the middle of bars.

What you describe is popular also and I'm absolutely not arguing with you but the A pillar support doesn't really transfer energy into the 1/2 lateral. The A pillar support mainly comes into play when the roof bars come down during a roll over impact. It is an opposite load path from what most people picture. The 1/2 lateral transfers energy into the A pillar support. Think of it as a last resort as the roof collapses. Triangulating the opening like you describe is fine and in fact we allow the A pillar support to be down a bit further for egress if done properly.

It is ok for a cage to deflect and bend. It must protect the occupants, no one cares if the cage doesn't survive. Energy is absorbed by stuff bending, sheet metal and tubes. Energy not absorbed or deflected by crush zones is then transfered into the occupants.

Years ago at an eastern short track they lost a couple drivers in a short period of time and studies showed it was because the cars were too tough. They guys would hit the wall and died from internal injuries...soft tissue and organ damage from the impact. No external injuries. Richard Petty pioneered a bit of this with NASCAR by making the suspension bits up front a bit weaker to fold up when heavily impacted. Old racing seats used to wrap around the rib cage only. Heart and spinal injuries happened a lot from side impacts. then someone figured out to spread that energy into the shoulder area also. Seats were redesigned and now seem a wonder of engineering techiniques and materials.

Anyhow, people tend to focus too much on worrying about cage deflection or a bar bending. If the cage prevents or minimizes injury that otherwise would have likely happened it did the job. It is not a crime to have to replace a few bars or even the car.

Gosh Dave, doing such good work making us all look bad. You should be ashamed of yourself

Question.

From the NASA rule book...
3.8.7.1 Shoulder Belts Reinforcement Bar
The transversal reinforcement shall be a tube measuring at least 1.5 inch x .120 inch or 1.6 inch x .095 inch, made from cold drawn seamless carbon steel. It is recommended that the bar be as close as possible to the seats.

Is this the only place CDS needs to be used in the cage? Is there a reason DOM cannot be used?

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Ckgtimk2
Question.

From the NASA rule book...
3.8.7.1 Shoulder Belts Reinforcement Bar
The transversal reinforcement shall be a tube measuring at least 1.5 inch x .120 inch or 1.6 inch x .095 inch, made from cold drawn seamless carbon steel. It is recommended that the bar be as close as possible to the seats.

Is this the only place CDS needs to be used in the cage? Is there a reason DOM cannot be used?

DOM is fine. Its just an oversight in the book. Blame Anders I've never seen 1.6 as a commercial tubing size either. NHRA requires 1.65 for their stuff.

Anyone care to give a reason why this seems to be the only .120 wall bar required?

Any other places in the cage/car prep where something thicker than .095 might be a good idea?

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alosix
Anyone care to give a reason why this seems to be the only .120 wall bar required?

Any other places in the cage/car prep where something thicker than .095 might be a good idea?

Nope, likely another oversight ....

Halfway useful thread dying a slow death here..

I like the look of the dimple dies used in some gussets, and plates used to tie the cage to the pillars/floor.

Any thoughts on those?

Sizes used?

Places they really shouldn't be used?

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alosix
Halfway useful thread dying a slow death here..

I like the look of the dimple dies used in some gussets, and plates used to tie the cage to the pillars/floor.

Any thoughts on those?

Sizes used?

Places they really shouldn't be used?

Largely its a look.
DTM wannabes purposely miss the A and B pillars by miles and then connect with these punched plates full of holes, then the next guy misses by a mile and a 1/4 and more gussets. And on and on.

Maybe somebody could exercise some care with the fit around any of the large holes in the bodyshell and just use discreet tabs....

Like most rally builders do.

---

John Vanlandingham
Sleezattle, WA, USA

Vive le Prole-le-ralliat

www.rallyrace.net/jvab
CALL +1 206 431-9696
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DTM wannabes purposely miss the A and B pillars by miles and then connect with these punched plates full of holes

No doubt.. I'd like to be able to still use the car for grass o cross. So being able to see cones could be handy.

Sounds reasonable. Given the thing gauge steel used there really isn't any meaningful weight savings (steering clear of McDonalds is more effective). Not really enough bends in the sheet to make it very strong either.

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john vanlandingham

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alosix
Halfway useful thread dying a slow death here..

I like the look of the dimple dies used in some gussets, and plates used to tie the cage to the pillars/floor.

Any thoughts on those?

Sizes used?

Places they really shouldn't be used?

Largely its a look.
DTM wannabes purposely miss the A and B pillars by miles and then connect with these punched plates full of holes, then the next guy misses by a mile and a 1/4 and more gussets. And on and on.

Maybe somebody could exercise some care with the fit around any of the large holes in the bodyshell and just use discreet tabs....

Like most rally builders do.

While I reckon sometimes that's probably true, it's not always the case. I hardly ever use tabs because I take the time to get a good enough fit that I can just stitch weld the tube to the A-pillar or B-pillar or whatever. However, there are some cases where that's not practical or possible. On Dave Hintz's BMW, for example, to be able to do that would have required tilting the main hoop at an angle and mounting the feet in a non ideal spot. Also, it would not have allowed enough room for the seat to go back. The answer was to make a plate to tie in the main hoop and span the small gap. The dimpled hole are not for decoration, they add quite a bit of stiffness to the plate.

Also, because I'm a cheap bastard I don't have any fancy dimpling tools. I just use some old half inch drive sockets and a piece of rollcage tubing held in a vice. And a hammer.

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Doivi Clarkinen
Also, because I'm a cheap bastard I don't have any fancy dimpling tools. I just use some old half inch drive sockets and a piece of rollcage tubing held in a vice. And a hammer.

Don't lie to us. We know you use the sledge side of a really big axe.

What thickness plate are you using for that sort of setup? Guessing thicker than the 18 ga we were talking about for gussets.

The main hoop on a 4 Door GD bodied WRX is kinda in no man's land with respect to tying it to something. I suspect you could plate it to the rear door opening if needed.

I've found a guy making the dies 'cheap' here:
http://www.pirate4x4.com/forum/showthread.php?t=871560

Trying to figure out what sizes to grab though.

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NoCoast

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Doivi Clarkinen
Also, because I'm a cheap bastard I don't have any fancy dimpling tools. I just use some old half inch drive sockets and a piece of rollcage tubing held in a vice. And a hammer.

Don't lie to us. We know you use the sledge side of a really big axe.

Only when I can't find my claw hammer.

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alosix
What thickness plate are you using for that sort of setup? Guessing thicker than the 18 ga we were talking about for gussets.

The main hoop on a 4 Door GD bodied WRX is kinda in no man's land with respect to tying it to something. I suspect you could plate it to the rear door opening if needed.

I've found a guy making the dies 'cheap' here:
http://www.pirate4x4.com/forum/showthread.php?t=871560

Trying to figure out what sizes to grab though.

14 ga for rollcage taco gussets and 16 or 14 ga plates to the body like I pictured. Something big like you would need for a 4 door Subaru I would go thicker or clamshell it from both side with thinner.

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alosix
No doubt.. I'd like to be able to still use the car for grass o cross. So being able to see cones could be handy.

the roll cage in Betsy blocks the view a little bit. but i don't think it really affects me in rally cross.

just don't go with too small of a steering wheel