some good roll cage buidling guides

Lina,
Bending tubing, everthing usually adds up to 90 degrees. Most cars have a 80 degree bend at the top of the hoop, so a 10* at the belt line. Now that can be 70-75 degrees and of course a 20 or 15* companion bend at the belt line. Gen1 RX7 and Talons are 2 cars that come to mind that have a more severe angle along the B pillar. 2002 are a bit more 'square'. The lower leg needs to be relatively straight up and down but may taper in just a smidge to allow for welding to the plate.

The door bars may be bent near the ends to keep them out close to the door and still hit the main hoop. usually 10* or so about 6 inches from the end.

This angle thing repeats along the A pillars with the 1/2 laterals. Usually you see something along the lines of 30ish degrees at the top and 60ish at the dash/bottom of windshield. This varies with the amount of rake on the windshield. Old Beetles and Saabs are nearly straight at the windshield so the top number is more like the main hoop, closer to 90*.

Our rules are a basic recipe. They have to be adjusted to fit different cars. We frown upon artistic interpretation however. The drawing of the RA cage shows the basic formula and minimum tubing size. This is a reference and not a cast in stone diagram.

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Littlelina
Hey everyone, Im back! - this time I have a car! decided to go with a 1971 bmw 2002 4sp.
Ive been "building" restoring and getting ready to put in a roll cage for the first time... I ordered the tubing and have all my article 253 and so forth... looking for a lead one good book I can use to help me through the process.
thanks

the one book I used in planning is called the Metal fabricators handbook it has a short chapter on roll cages and there were useful tid bits. but all you guys were the most helpful and especially you know who
happy holidays

Your rally car is going to have a fireplace? SWEET!

---

Grassroots rally. It's what I think about.

screw a new heater core and fan motor, i want that mod!

I see, hang the main hoop on the fireplace and hope Santa brings a Quattro S2...clever!

RS6 is all ive ever wanted for xmas
Glad I can bring something new

Mods wise to phorum..my mom said the cutest thing..."dont let it get too hot"

Okay. Here's a good question.
For the transverse member attaching the two front half laterals. AKA the bar that connects the two half laterals at the top of the windshield/a-pillars. (253-3). The only reference to that bar is in 8.3.1. I've seen cages where it is bent and others where it is not. I know for the roof reinforcements it states they "may follow the curve of the roof" implying that they can be bent to get closer and follow the contour of the roof. But what about the transverse bar?
The most common I have seen is a single bend in the middle of the bar. Any thoughts?

It is defined earlier:


8.2.8 Transverse member :
Near-transverse single piece tube joining the upper parts of the
lateral half-rollbars or of the lateral rollbars

Looking at the other definitions, where bends are restricted, they seem to be explicitly restricted. The design intent of the upper portion would tend to say follow the roofline.

I have two bends in my tranverse member, didn't hear anything from Hurst when he reviewed the design.

I've seen several with the 2 bends in them. I was staring @ this Jackson Rally built setup earlier today online.

Seems like people love to make the blue Subie cages that way, even though its against the rules. Maybe its a homolagated kit, or how the one in the magazine looked?

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alosix
I've seen several with the 2 bends in them. I was staring @ this Jackson Rally built setup earlier today online.

That is just absolutely terrible.

Edit: Oh wait, it's just dropped down for welding, it's not up in position yet. Still not so sure about that design. Seems like it might reduce headroom and not fit as tight to the roof as it could.



Edited 1 time(s). Last edit at 11/30/2011 06:36PM by Doivi Clarkinen.

Yeah, that bend looks a bit extreme. And I'm not sure how the half-lateral to main hoop reinforcement is legal, looks to obstruct way too much of the opening.

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Doivi Clarkinen

That is just absolutely terrible.

Edit: Oh wait, it's just dropped down for welding, it's not up in position yet. Still not so sure about that design. Seems like it might reduce headroom and not fit as tight to the roof as it could.

Fail on my part there. That cage does fit pretty darn tight up to the car when its in place. That was just the best pic I found of the bent transverse with the rest of the top of the jungle gym on display.

FWIW, the custom cages fia kit for the GD body cars is setup pretty close to that. Might be where its coming from.



Edited 1 time(s). Last edit at 12/01/2011 09:29AM by alosix.

Near transverse means nearly straight. A couple of small bends to keep near the roof is one thing....I wouldn't log the cage shown as the front bars are a mess in my opinion. That's one I'd get Hurst to sign off on. There is no reason to build a cage like that, just someone trying to be clever or artistic.

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heymagic
There is no reason to build a cage like that, just someone trying to be clever or artistic.

Everybody is a creative genius.

It's easy Gene:
a) I sar-d some totally baller pics on Facebook so I tweeted my brah
b) built way cool cage.
c) looks like what I saw, so it must be ball-er, and I must be super-baller-er since it's so unique.

That's the way it goes, dude.

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John Vanlandingham
Sleezattle, WA, USA

Vive le Prole-le-ralliat

www.rallyrace.net/jvab
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