Help me design a roll cage...

[Rezarf]

Here are some of Adam's old cruiser that I really like. Metal tech has more triangulation and Adam's attaches to the dash...

I think something like MT's front bars, with something like this out back should be easy enough. I would imagine the hard part being tying the cage into the frame... but still not that hard.

Root, if your reading this do you care if I ask Mark to toss the front bars onto the stuff for you and matt?

Drew

 

[subzali]

Drew, MT makes frame tie-ins as well, which make that job just a little easier. There's not much triangulation in those pictures you just posted, I would be a little nervous about it in a rollover; it would more than likely tweak.

 

[isotel]

Adam's attaches to the dash...

Sweet Rig, Nice Color, and a Horrible way to mount a cage the lack of triangulation is no good either.. There is nothing wrong with a simple Boxy looking cage, but the Angled Spreaders will keep it from folding up in a major roll..

I like the fact that i have to step over my Door Bars to get into my rig.. makes me feel safe, Tied In, and Protected.

 

[daisydog34]

Sweet Rig, Nice Color, and a Horrible way to mount a cage the lack of triangulation is no good either.. There is nothing wrong with a simple Boxy looking cage, but the Angled Spreaders will keep it from folding up in a major roll..

I like the fact that i have to step over my Door Bars to get into my rig.. makes me feel safe, Tied In, and Protected.

I also agree that there is too little triangulation in this cage. The other thing that I have seen a lot of in these MT cages is there is no lateral(side to side) triangulation. I have had to fix customer cages that didn't want this form of triangulation because it would get in the way. They have a semi-hard flop and the whole top of the cage bends. It doesn't necessarily have to be an "X" in the main hoop but gussets in the main hoop and windshield can do the trick.

 

[Rezarf]

So I have read a ton about designing a cage. Seems like intersecting tubes and triangles are key. I haven't found any certain answer for why a Halo is better or worse than a non halo design.

Can you guys enlighten me?

Thanks!

Drew

 

[Uncle Ben]

I like halo designs because they make more of a box than a wheel. That said I dislike "covered wagon" style family bars like Adams you have pictured because I don't care for the look.

 

[Rezarf]

I like this one... anyone know the owner? Seems hardcore

Seriously though, UB I like these lines, I would add Metal Tech front profile bars and maybe a halo out back but I like the lines of your cage.

 

[ElliottB]

2 crossbars between the A and B pillar would make that cage signifcantly stronger. Didn't these guys take shop class back in high school? Triangulation = teh win!

 

[Red_Chili]

The back portion doesn't even look like it would hold up in a gentle roll... Just sayin'. I would be concerned that the rest might parallelogram on you.

Yep, triangulation. Let the design carry the burden, rather than the thickness etc. of the steel.

 

[DaveInDenver]

The back portion doesn't even look like it would hold up in a gentle roll... Just sayin'. I would be concerned that the rest might parallelogram on you.

I think the rear tubes might bend in but the main bar and cage I think would very likely hold up.

Maybe the cross bracing a little higher on the tube behind the seat, like nearer to the upper bend, I dunno (say swapping how the rear angling tube and the side angling tube connect). Mostly I'd like to see that since there is no cross member lower down between the main hoop near where the diagonals members tie in. I'd also probably like something diagonal between the fore/aft halo tubes overhead, but probably not strictly necessary.

Really does seem pretty decent and still not look like an erector set, though. I think it's fundamentally all there, nice job. From what very little I know, with the addition of diagonals at the doors this would probably meet NHRA/IHRA 10-point cage requirements.

 

[nakman]

Yeah but since there's no rear seat, and no rear passengers, who cares of those back pieces bend in a little? those B pillars look rock solid to me, being triangulated in two directions like that.. that's a fine cage, IMO, for this vehicle's purpose. If this was for the OP, with kid seat(s), then I'd say put another stick across the top in back.

But with no cross bar in back you can still move a refrigerator or hot water heater...

 

[DaveInDenver]

I should add that with door members (and probably a mid-way horizontal behind the seat), being a NHRA 10-point cage means it would be kosher for under 10.99 cars. Think Wild Rice could break 11? Imelda doesn't even need a bar at all under the rules...

 

[subzali]

what's a halo tube?

 

[DaveInDenver]

Halo would be just like it sounds, a hoop that goes under the roof from the main bar to the windshield over your head, imagine an angel's halo. Kevin's isn't technically a halo, although the tube running between the two side hoops would be functioning as the halo tube in this case. The alternative would be a real halo, which would be like the bill on a cap over your head. Then there would be two A-pillar tubes that go from behind the windshield to the floor. I think the reason doing a halo is preferred for racing is that there is no joint on the parallel tube that runs behind the top of the windshield, but I guess they are harder to fab.

All cages start with a 'main hoop' typically, then Kevin's design would be called a 'forward hoop' design. The forward hoop goes from the main hoop under the roof line down the A-pillar and to the floor. A halo type would have a 'halo loop' that goes from the main hoop to the top of the A-pillar, across the back of the windshield and back to the main hoop. There would then be two A-pillar tubes from the front corners to the floor. There is a third option where there is a 'front hoop' that goes from the floor up the A-pillar, across the windshield and down the other A-pillar. There would be two side stringers connecting the front and main hoop at the top, under the roof. This is like Adam's earlier in the thread.

I attached a racing halo cage. See the top hoop? That's a halo.

 

[Red_Chili]

The back portion doesn't even look like it would hold up in a gentle roll... Just sayin'. I would be concerned that the rest might parallelogram on you.

BTW, it just dawned on me that that is Wild Rice. Duh. There's a lot I cannot see in the pic. If UB designed and built it, it is better than anything I could build.

 

[subzali]

Thanks Dave, never knew it would make a difference how it was welded up.

So the Metaltech cages are also a "forward hoop" design, and they do not incorporate any kind of halo.
http://metaltech4x4.com/productsframeset.htm

So is there really any advantage to having the halo vs. say a "forward hoop" design? Does the way it welds up really make a difference in strength? Is that an 8 point or 10 point cage you posted up Dave?

 

[Uncle Ben]

Thanks Dave, never knew it would make a difference how it was welded up.

So is there really any advantage to having the halo vs. say a "forward hoop" design? Does the way it welds up really make a different in strength? Is that an 8 point or 10 point cage you posted up Dave?

Let me explain dynamics of a "good cage" by example....
H or O which one of these end profiles would you want to be in when you slip off of that rock on a shelf trail?

 

[subzali]

I know you want to be as square as possible to prevent multiple rollovers, I've seen you type that before . A flop is "okay", an end-over-end is not.

 

[DaveInDenver]

Thanks Dave, never knew it would make a difference how it was welded up.

Does the way it welds up really make a different in strength?

Welds are more likely to fatigue or crack, they are points that are done under less controlled and uniform conditions than the original tube. In a car or closed cab truck they are more difficult to do, so I think there's a natural tendency to distrust them by sanctioning inspectors.

A car roll is likely to be high speed multiple roll and morph from a side to end-over-end or some combination, which is why they are more concerned with a halo than a rock truck that will be more likely a side flop at slow speed. Of course you have to weigh that it might accelerate as in Kevin's shelf road example.

How you then build the cage is also impacted with how you fit the thing in your car, since they are a lot tighter spaces than a FJ40 with it's top off. There's multiple steps, tipping and welding. What a jigsaw puzzle it was when my buddy put his 10-point in his big block Nova. The number of welds and where you have to do them makes certain configurations work better than others.

Is that an 8 point or 10 point cage you posted up Dave?

The attached photo is a 10-point cage.

 

[subzali]

Got my basic MetalTech cage done at lunch today...I have a couple tubing mods I'd like to pass by you guys and see what you think/what they do.