Help me design a roll cage...

[AxleIke]

Needs some triangles behind the front seats, or it'll fold on a side impact.

Personally, I'd do something across the dash in the front too, and put a diagonal cross piece in the rear hoops.

Also, gussets in all the corners.

 

[corsair23]

Dude...You're getting married and I can only imagine that sometime in the near future there will be some kiddos coming along? Unless you are planning to ditch the 40 at that time then why not go ahead and do the family cage thing now at the same time?

More cost now for sure but you won't have anymore $$ in the future than you do now, trust me

 

[subzali]

Dude, this project is like a long way off as it is, and all I'm really doing is getting some practice at AutoCAD. At the moment I'm kinda thinking that even once kiddos come along the 40 will remain a 2-seater and we will need a substitute for family trips (hint: 80s and even 100s are getting cheap)

At the moment what I have is just a basic cage from Metaltech and I will be adding things to see what works and what doesn't. Isaac, I would really like a bar across the front but am not sure how to do it because eventually I would like to get a locking dash box - most bars go across the top of the dash pad area so a box that opens up there wouldn't work. Still trying to think of how to accomplish that one...maybe have it under the dash pad? I dunno... I will also be adding something that angles up from the foot area to the main hoop as well as triangulating behind the seats as you say...

 

[AxleIke]

Dude, this project is like a long way off as it is, and all I'm really doing is getting some practice at AutoCAD. At the moment I'm kinda thinking that even once kiddos come along the 40 will remain a 2-seater and we will need a substitute for family trips (hint: 80s and even 100s are getting cheap)

At the moment what I have is just a basic cage from Metaltech and I will be adding things to see what works and what doesn't. Isaac, I would really like a bar across the front but am not sure how to do it because eventually I would like to get a locking dash box - most bars go across the top of the dash pad area so a box that opens up there wouldn't work. Still trying to think of how to accomplish that one...maybe have it under the dash pad? I dunno... I will also be adding something that angles up from the foot area to the main hoop as well as triangulating behind the seats as you say...

The dash bar is something that I've always hated in the mini world too...

I don't know how a 40 heater system is set up, but to me, the ideal way would be to come down right next to the doors, through the dash, and put the spreader behind everything for an ultra clean look.

As for behind the seats, the most practical, to me anyway, seems to be to go from low on the passenger side to high on the driver. This gives the easiest access for kiddos to get into the back area, or even for access to tools on a 2 seater...Passenger side being the easiest access since there is no steering wheel.

 

[subzali]

heater in a 40!?

No seriously, a 40 only has a heater in the center, right in front of the shifter, so in theory you could do what you're talking about, except for in my case with the locking dash box.

Why not do a full X behind the seats? Won't it fold if you roll onto the passenger side if you have it the way you describe?

There are pretty good pictures of how the MT cage works on their website:
http://www.metaltech4x4.com/productsframeset.htm

 

[AxleIke]

heater in a 40!?

No seriously, a 40 only has a heater in the center, right in front of the shifter, so in theory you could do what you're talking about, except for in my case with the locking dash box.

Why not do a full X behind the seats? Won't it fold if you roll onto the passenger side if you have it the way you describe?

There are pretty good pictures of how the MT cage works on their website:
http://www.metaltech4x4.com/productsframeset.htm

Full X is better, but the single triangle seems to be enough, at least from what I've seen.

As for the dash bar and the box, why not just drop it a bit lower, so it would sit with the top of the bar right at the top of the lower part of the dash box?

I'm very surprised the MT cage doesn't have anything behind the seats...Not saying its a bad cage or anything, but from all the research I've done, everyone says the behind the seats triangles are pretty critical.

MT seems to make very good products, so I'd assume they know their business. I'd be curious to see some solid works stress loading on their design.

 

[subzali]

What about a horizontal bar across the back of the seats with angled legs like the picture Dave posted a page or two back?

With the dash bar I'm thinking the same as you - just have to see if it would actually work that way and not interfere with knobs, controls, or instrument cluster.

 

[Uncle Ben]

design the rear spreader to be a point for your 5 point harnesses even if you don't have them now! From that bar you can design your triangulation. A single diagonal bar is all that is needed. Trouble with an X bar is you end up with one cross bar and 2 butt joints. You add twice as much weight and the butt joint weld will case harden the cross bar, creating a "fault line"

 

[Uncle Ben]

What about a horizontal bar across the back of the seats with angled legs like the picture Dave posted a page or two back?

With the dash bar I'm thinking the same as you - just have to see if it would actually work that way and not interfere with knobs, controls, or instrument cluster.

My cage has the two angled legs from the rear spreader. It has stayed tru through 4 flops and one bad roll over. The front hoop has tweaked however and desperately needs some triangulation.

 

[corsair23]

There are pretty good pictures of how the MT cage works on their website:
http://www.metaltech4x4.com/productsframeset.htm

This is going to hurt...

I bet this one did hurt ...

 

[subzali]

I heard that everybody was out for lunch when that tree fell, so nobody was inside. But it had just been restored so yes it did hurt a lot

 

[subzali]

Latest:

I spent a couple minutes today adding a couple things. I did an Uncle Ben style spreader behind the front seats, plus a bar connecting the A pillar to the B pillar, and triangles in the rear hoops. Comments?

(Drew I hope you don't mind me hijacking the thread - it's all on the same topic so I thought it might help?)

On the second picture I have a Dave-style spreader based on the roll cage picture he posted up a couple pages back, and I removed the triangles from the rear hoops. Thoughts?

 

[Rezarf]

I dig these designs...

 

[Rezarf]

On the green cruiser especially with something like the Metal Tech from profile bars.

 

[Rezarf]

Bump, can you guys tell me how the green one is made? It is hard for me to tell but it looks like the A and C pillar are from the same tube? With the B pillar being a straight section?

I think this is the way I am heading with metal tech's front profile tubes.

So, my question is, can I create a hoop with the B pillar (think stock) and then tie the front and rear pillars into that one, or am I starting to jack with the integrity of the design? I would figure once welded properly it should work either way?

 

[Uncle Ben]

Drew, get a hold of Jerry! I think you will really dig the cage that Tyler (daisydog34) and Aaron are building for him!

 

[Rezarf]

You got it Kevin, thanks.

Drew

 

[bustanutley]

Here is what my cage looks like:

and it holds up fine:

If/When I rebuild, the A-C stringer will be one tube. Having a B-piller hoop sucks, it gets hung up on things, being one smooth surface is superior. As far as HREW and DOM, use DOM on the exterior tubes and HREW in interior bracing to save on cost. DOM it tougher, not stronger, they have identical strength properties but the extra cold working makes DOM dent resistant. My cage is mostly HREW, the A-pillars are DOM. My B-piller is pretty beat up…

 

[farnhamstj]

Subzali, might as well plan the family portion of your cage with integrated rear bench mounts too.