some good roll cage buidling guides

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john vanlandingham
Yeah no problems. The integrity of the stink floor isn't important so yeah cut up the floor where the MAIN hoop directs force into when the car flips.
Weld quality isn't important, and millions of guys have been doing and telling others to do it for centuries with no thought at all to the fact that the thin flimsy sheetmetal , blobbed back by amateurs calling a collection of rat turds "welding" might be better reinforced rather than sliced up..

And don't pay any attention to those worry warts who build boxes with separable tops so they can slid off the top and drop the cage 4" to access the tops of the tubes. They're probably worried more about survivors suing them that ease of construction. Fawk them.

I sometimes have no clue what you are talking about.
We build boxes and can drop it 4-6". The L cut and bend is easy.

The main hoop has an X. Why have more weight and bars and gussets when you can do the V.
Yeah, that design you posted is exactly how I would build cages if it were legal. It's not anymore, main hoop X is required, thus it's no longer my preferred design.

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john vanlandingham
Yeah no problems. The integrity of the stink floor isn't important so yeah cut up the floor where the MAIN hoop directs force into when the car flips.
Weld quality isn't important, and millions of guys have been doing and telling others to do it for centuries with no thought at all to the fact that the thin flimsy sheetmetal , blobbed back by amateurs calling a collection of rat turds "welding" might be better reinforced rather than sliced up..

And don't pay any attention to those worry warts who build boxes with separable tops so they can slid off the top and drop the cage 4" to access the tops of the tubes. They're probably worried more about survivors suing them that ease of construction. Fawk them.

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I sometimes have no clue what you are talking about.

Really?


Well I know what you're talking about in reccomending a later car..

I think that's crazy talk. Think of this:


Thats kind of what a 2002 spindle looks like but with much smaller bearings.
That may make some folks blanche but think of how light those bearings must be compared to the later things with spindles like this:


Sure a large diameter tube is orders of magnitude stronger, byt ! I bigger spindle means a larger wheelbear!
What?ou can see the problem? OK its going to be much stronger and more relaible, but! It will weigh more!
And weight is the enemy.
Bearing failures are a small price to pay for saving some fab and weight.
How often does this happen?

---

John Vanlandingham
Sleezattle, WA, USA

Vive le Prole-le-ralliat

www.rallyrace.net/jvab
CALL +1 206 431-9696
Remember! Pacific Standard Time
is 3 hours behind Eastern Standard Time.



Edited 1 time(s). Last edit at 11/12/2011 09:32PM by john vanlandingham.

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Ascona73

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NoCoast
Think about how you are going to weld the tops of the tubes. We cut the floor so the main hoop can drop down to get access. Others remove the roof skin altogether.

My favorite method is to build raised platforms to weld the cage feet to. Allows the loads to be spread over numerous planes, and you can fit everything first prior to welding. Then you remove the base plates, and lower the cage to allow access to the top for welding.







Here you can see the platform spreads the loads over a greater area compared to going directly to the floorboards. Loads are on the floor, on the vertical surfaces of the inner sills (double shear), and on top of the inner sill.

That is exactly how my cage was done, but i don't think he used 3/16 plate for it...

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Ascona73

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NoCoast
Think about how you are going to weld the tops of the tubes. We cut the floor so the main hoop can drop down to get access. Others remove the roof skin altogether.

My favorite method is to build raised platforms to weld the cage feet to. Allows the loads to be spread over numerous planes, and you can fit everything first prior to welding. Then you remove the base plates, and lower the cage to allow access to the top for welding.





Wow....Nice!
Here you can see the platform spreads the loads over a greater area compared to going directly to the floorboards. Loads are on the floor, on the vertical surfaces of the inner sills (double shear), and on top of the inner sill.

what car were those for do you have any pics of them in/on the car
are those meant to be stands for the thing while its being constructed before assembly inside car? thanks
I like the way they look and think it will work for me can start making on tuesday

Make something like that that gets the tube even with the top of the sill, tack them in. Fit the main hoop and all the bars, tacking things together. When you are ready to commit to final welding of the structure, cut the tacks, remove the tie in plates, and drop the cage down to weld the tops of the junctions, and don't forget your gussets! You may need to use a ratchet strap to pull the legs together to drop down enough ect.

Make sure you think EVERY weld step through before you do it, it would really suck to realize you can't get to that last weld because you rushed something.

BTW, I have never built a cage, and probably won't for a long time. I feel somethings are better left to the professionals.

Those boxes are what the cage legs stand on when it is permanently installed in the car. You need to get with a scrutineer before you start building! It is very difficult to recover from mistakes when building a roll cage.

In response to Johns sarcastic remarks about parts availability, the BMW 2002 has an astounding amount of dealer support. Other great resources are www.realoem.com and Ireland Engineering.

Case in point is the 1967 2002 that I was working on two weeks ago. The car was leaking and getting moldy inside (luckily no rust yet). The customer wanted all new seals and a windshield. I was skeptical about parts availability. It turned out that I could choose between World Pac, Real OEM and the dealer on several items. None of the parts were outlandishly expensive considering that the car is 34 years old. It is really nice to be able to have a car with new window, trunk and door seals!

I like the 2002 and it makes a good race car. The only thing that bugs me so far is the weird pedal box and the odd single shear front control arms. The cars work well on tarmac rallies, just look at Targa Newfoundland. The 2002 would probably be just fine on smooth gravel. I don't know if they are strong enough "out of the box" for rough rallies.

---

Robert.

"You are way too normal to be on Rally Anarchy." Eddie Fiorelli.

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Littlelina
what car were those for do you have any pics of them in/on the car
are those meant to be stands for the thing while its being constructed before assembly inside car? thanks
I like the way they look and think it will work for me can start making on tuesday

Those are for my Opel Ascona. I figure that since the car has to weigh 2271 lbs because of my engine size, I might as well put the weight into strengthening the car and making it safe. No pics of the cage installed because there's plenty of rust repair left to do. Hence the new inner rocker panels...

I haven't touched the car since last June. There's always another project that takes precedence it seems.



Rockers were mighty rusty, especially the passenger side. But this car spent a lot of time in Vermont.


However here's a WRX I did a few years ago for road racing. Same type of baseplates.

Driver's side main hoop.


Driver's side forward hoop.

Oh my... dat's purrty!

Lina:

I will most likely be the scrutineer that will be inspecting the car. My suggestions are that you follow the R-A rulebook (and FIA article 253), as cages built to those rules will be accepted at both NRS and R-A events.

My further suggestion is that you make really sure of how it should be and make it really clear to the builder what needs to be done. One of the problems with having a road race builder doing it is that they have preconceived notions of how a cage should be, and it often difficult to convince them that rally cages are somewhat different.

By all means draw up cage design proposal and send it to either Gene or me for review. You can also have the cage-builder call me if he has any questions.

I can make trips up to Santa Rosa to check things out if necessary, but probably not until after Christmas.

-michel

I just want to see you weld that aluminum tube to that steel plate, Bob. Oh wait, what am I thinking, you could probably do it.

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NoCoast
The main hoop has an X. Why have more weight and bars and gussets when you can do the V.
Yeah, that design you posted is exactly how I would build cages if it were legal. It's not anymore, main hoop X is required, thus it's no longer my preferred design.

Appendix J cages do not necessarily require an X in the main hoop. But, you would have to build out of CDS.

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wvonkessler

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NoCoast
The main hoop has an X. Why have more weight and bars and gussets when you can do the V.
Yeah, that design you posted is exactly how I would build cages if it were legal. It's not anymore, main hoop X is required, thus it's no longer my preferred design.

Appendix J cages do not necessarily require an X in the main hoop. But, you would have to build out of CDS.

My interpretation is the main hoop X has been required for almost 10 years on new construction built to App. J.

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Cars homologated as from 01.01.2002 :
The cage must have two diagonal members on the main rollbar
according to Drawing 253-7.
Members must be straight and may be removable.
The lower end of the diagonal must join the main rollbar no further
than 100 mm from the mounting foot (see Drawing 253-52 for the
measurement).
The upper end of the diagonal must join the main rollbar no further
than 100 mm from its junction with the backstay.

253-7 is a drawing of a main hoop X.



Edited 1 time(s). Last edit at 11/14/2011 09:59AM by fliz.

If you have an old car that was homologated back when the V was allowed you can still do it as Wilson mentioned. Has to be CDS and built exactly to the required FIA spec of the time. I would only advise this if someone where building a replica for some goofy reason

For all practical purposes you need an X .

OK. I still don't quite understand how the whole "homologated car" thing works.

Does the 7 year expiration come into play, also?

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251.2.1.7
Homologation of a series-produced car will become null and void 7
years after the date on which the series-production of the said
model has been stopped (series-production under 10 % of the
minimum production of the group considered)