Newb cage questions:

Studying the FIA cage diagrams I'm struck by how I think it might be easier to use the two lateral bar construction over a main a front roll bar construction. Pro's and cons of the two designs? For some wacky reason, I think I can get a tighter fit with lateral bars, but I might be talking out my ass since this will be my first cage.

For a new cage it looks like I need a roof X, a rear X (in the hoop or between the lateral bars), a dash bar, a sill bar and a door bar, and windsceen pillar bars (basically 253-35C). Just confirming I'm reading this right.

Gussets. Where do I need those? That's the one I'm having a bit of trouble with.

8.3.2.1.5 Reinforcement of bends and junctions :
The junctions between:
- the diagonal members of the main rollbar,
- the roof reinforcements (configuration of Drawing 253-12 and
only for cars homologated as from 01.01.2007),
-the doorbars (configuration of Drawing 253-9),
- the doorbars and the windscreen pillar reinforcement (Drawing
253-15),
must be reinforced by a minimum of 2 gussets complying with
Article 253-8.2.14.
If the doorbars and the windscreen pillar reinforcement are not
situated in the same plane, the reinforcement may be made of
fabricated sheet metal, provided it complies with dimensions in
Article 253-8.2.14.

Someone have a picture that shows where you need them?

Thanks

You need gussets anyplace where there is an X.
There are templates to download on here made by Tim Taylor, but I know where they are easier on my site.
http://nocoastmotorsports.net/Build/Resources/Gussets/

Here's the places you need them.


If you do a roof X, you will need to gusset that as well.

If you do not do a door X, you will save yourself 8 gussets also.

This is a pretty min spec cage:


Notice the sill bar plus a single door bar and a-pillar reinforcement all meet at bottom of half lateral.

Main hoop, two half laterals, windshield longitudinal member, roof V, main hoop X, two sill bars, two door bar, two a-pillar reinforcements, and two rear back stays. I always add the main hoop to half lateral support. Options are rear V and lower main hoop to rear stays.

---

Grant Hughes

You should really get in touch with the inspector who is going to certify it. Save yourself some time and heartache

Are you talking 253-1 or 253-2 ? And what car?

Rally-America.com/rules has an illustration of their minimum cage requirements, its a decent enuf sketch.... Looks like your in Canada so I would find a local scrutineer and ask him... cARS may differ..

---

I be sorry as a muthafucka I did, still sorry I did n' hustled ta peep what tha fuck I holla'd a lil' bit better, or at least try to.

Quote
heymagic
Are you talking 253-1 or 253-2 ? And what car?

For reference:



Isn't 253-3 the only legal method for R-A?

Edit: and this is where I notice the O/P is in Canada.



Edited 1 time(s). Last edit at 03/07/2013 09:08AM by Nubby.

I think the others are technically legal but I don't know why you would...
253-3 is the only smart one.

---

Grant Hughes

Car is a GD NA. I'm building to CARS rules, which I think are also NASA.

Why is 253-3 the best option?

Gussets are only needed for crossed bars. And for cars after 2002 you need a rear hoop X, so this this the minimum number of gussets, correct?

I will get in touch with a CARS inspector ASAP.

Thanks.

Quote
NoCoast
I think the others are technically legal but I don't know why you would...
253-3 is the only smart one.

And that 252-2 is the source of the initial misunderstanding on "all elements in the front must be 1.75", which, in the way it always goes, became carved in stone and heels dug in the second it was questioned..

FIA meant that IF you did 253-2 or -1 THEN all the tubes must be big...
If sense prevailed, a person would do -3 and the forward legs and windshield bar could be in 40mm tube x whatever..

Got that answer from the biggest cage supplier builder in Sweden who said "I saw that and thought those idiots can't be serious!! So I called Svenskabilsportförbundet and asked them to calrify cause its stupid. They called FIA and got the answer. 40mm stands, we can't get the radius right and get the forward bits close so its worse if we're away"

---

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.

Unless you are building to exact FIA regs including homolgation , CDS tubing and all you need an X in the main hoop.

So look at the pictures/drawings and keep in mind these FIA cages are used for other than rally cars sometimes.

253-1 is the old VW bug or CJ5 cage. It doesn't fit well in modern shells but it is better than 253-2. The bends in the illustration are not even close to scale, they are too sharp and tight. In reality you will be using something along the lines of a 6inch radius die. The bends will be much larger. So if using 253-2 the connecting bars will either be too low, too far back or over top of your helmet. The main X will also be a mess. That configuration has no place even being shown in the books for modern cages. 253-1 is only slightly better but again the connecting bars will need bends on both ends to hit the main hoops. The front hoop will need a complex bend at the bottom of the windshield pillar to match the A pillar curving both back and in. The hoop will not align well with the windshield opening going across the car. The odds of you building a cage that will be allowed to compete are very skinny honestly. Beyond getting a log book the car will have to be accepted at events as well and cages have been rejected over design concerns.

253-3 allows the best fitment in a passenger car for dual occupants, that is why it is used in 99.9999999% of all rally cages world wide. The main hoop fits the compartment the best, the 1/2 laterals are easy to tailor to the interior and the windshield bar fits the opening with 2 small adjustments and a twist.

Seriously, there are lots of great pics on how to do a cage for your car correctly (look at Grants above). Stray from that formula and the odds of a do-over increase rapidly.

Ok, 253-3 it is. The main hoop needs to be 1.75. Can the half laterals be 1.50 and woud you want them to be?

Links to pictures always appreciated.

The 1/2 laterals need to be 1.75 to be accepted at RA events The main 6 point cage , 4 legs and 2 backstays need to be 1.75 and one door bars for majority acceptance. Secondary bars can be 1.5. I normally ise 1.75 for all of it myself although I have some 1.5 to ad in on the next cage I do..someday, maybe.

Quote
NBS2005
Gussets are only needed for crossed bars. And for cars after 2002 you need a rear hoop X, so this this the minimum number of gussets, correct?

Main hoop X, yes.

In the rear, you can be legal with only two bars total, back stays. We usually do the rear V and have started doing the lower main hoop to rear stay bars as well. With a GD (expensive car), I'd suggest doing the full shebang, including strip down, seam weld, and gusset and weld cage to shell anywhere any everywhere possible. Too expensive of shells to treat the shell as kinda disposable.

---

Grant Hughes

Quote
heymagic
The 1/2 laterals need to be 1.75 to be accepted at RA events The main 6 point cage , 4 legs and 2 backstays need to be 1.75 and one door bars for majority acceptance. Secondary bars can be 1.5. I normally ise 1.75 for all of it myself although I have some 1.5 to ad in on the next cage I do..someday, maybe.

Gene do all the tubes need to be 1.75" to be ACCEPTED at a RA event or to be LOGBOOKED by RA? Are cars to other organization's specs, like NRS, being rejected at tech at RA events for this reason? Is CARS following this spec too?

BTW, the 253-2 cage construction has a weakness that has not been mentioned. Any roof level joint is a very serious weak point in a cage; these joits all shold be reinforced in some fashin in modern cagae work. The 253-3 connection at the main hoop can be well reinforced with the diagonals beside the helmets shown in the lower pix in the 2ned post in this string (which are a bit too long in that pix, IMO). How to do that with the 253-2 construction is a problem that COULD be solved, but it is not conventional in cage building and there are no good bracing diagrams around for that. That leaves the joints at the top of the A-pillars and again, the solutions for the 253-2 design are not well documented and established....and would be in your line of sight anyway!

So yes, 253-3! Regards, Mark B.

Mark,

RA rules state all entries must meet RAs safety standards. There have been a couple cages rejected that I have heard about due to differences in design. I personally haven't done that and I don't think most regional scrutineers are doing that but technically they could.

CARS accepts logbooks and safety rules I believe.

I think most everybody in my neighbor hood uses the RA ruleset anyway as the NRS presence has dwindled away up here (sadly).

That could all change this year maybe. Hopefully. Wishful thinking I suppose.