Roll cage front tube placement

[vette427sbc]

Getting close to dropping the car off for a cage... is there a reason for placing the front tube at the kick panel? I would like to end it on top of the frame near the Z-bar bracket. Seems like it would be way easier to weld and provide (marginally) better support since it is further forward on the frame. Why is it that all cages I see are mounted at the kick panel?

 

[SuperBuickGuy]

it's a lot easier to mount there

if you have a dash bar, that location is the natural terminus for for the upper bar and the door bar

most rules require the bar to intersect there

 

[vette427sbc]

ahh did not think about the door bar... that makes sense. :3rd:

 

[SuperBuickGuy]

err... dash bar.... sorry

oh yeah, and if the bar is higher in the space where your foot needs to travel to get under the steering wheel; it's more of a PITA to get into the car

 

[vette427sbc]

I dont think Im going to be running door bars... The Corbeau seats, non tilt column and sidepipes already make it interesting to get in and out.

 

[Twin_Turbo]

Run a low or a bent bar it will not help as much but it will add some torsional rigidity

 

[SuperBuickGuy]

I dont think Im going to be running door bars... The Corbeau seats, non tilt column and sidepipes already make it interesting to get in and out.

You just said the exact reason mine doesn't have door bars - it will, but at this point I'm just not clever enough to find the spot where they will go past the seat, not over the door handle, not into the door pull, between my elbow and shoulder blade, and somewhere so I have at least a chance of getting out - all while preserving the door panel (which is probably my biggest impediment to success - that I don't want to make a door panel), I'd seriously like to run a door bar and a brace bar from the riser to to the triangulated point next to the seat....

 

[redvetracr]

my cage was designed, bent up and installed long before there was a Chevy Power Book but I always liked this one designed by the GM engineers.
http://www.vettemod.com/tech/ChevyPower.pdf

 

[SuperBuickGuy]

my cage was designed, bent up and installed long before there was a Chevy Power Book but I always liked this one designed by the GM engineers.
http://www.vettemod.com/tech/ChevyPower.pdf

I have that Chevy Power book.... and I don't see a cage - maybe you can point blind-me in the right direction? :crutches:

 

[redvetracr]

my cage was designed, bent up and installed long before there was a Chevy Power Book but I always liked this one designed by the GM engineers.
http://www.vettemod.com/tech/ChevyPower.pdf

I have that Chevy Power book.... and I don't see a cage - maybe you can point blind-me in the right direction? :crutches:

click the link wait for it to load and scroll down to page 6-3, it`s in the Corvette section

 

[SuperBuickGuy]

my cage was designed, bent up and installed long before there was a Chevy Power Book but I always liked this one designed by the GM engineers.
http://www.vettemod.com/tech/ChevyPower.pdf

I have that Chevy Power book.... and I don't see a cage - maybe you can point blind-me in the right direction? :crutches:

click the link wait for it to load and scroll down to page 6-3, it`s in the Corvette section

yep, blind as a bat.... there it is, Illustration 5

That interests me, I'd think the door bars would go down to the frame... does that structure strengthen the frame as well?

 

[redvetracr]

[/QUOTE]
That interests me, I'd think the door bars would go down to the frame... does that structure strengthen the frame as well?[/QUOTE]


I`m no structural engineer but looking at all that triangulation I would think it stiffens the frame.

 

[SuperBuickGuy]

That interests me, I'd think the door bars would go down to the frame... does that structure strengthen the frame as well?[/QUOTE]


I`m no structural engineer but looking at all that triangulation I would think it stiffens the frame.[/QUOTE]

me neither - though I play an expert in construction litigation as a day job.

the reason I ask, the shape is akin to a building truss, and those trusses are not as strong when you pull from the bottom, cross board... that said, a truss is better than no truss, and that would resolve the issue I'm having locating a space for that bar

 

[Bobbsbags]

When I was adding structure to my car, I built a little balsa model of the frame and twisted it with an arm and some hex nuts. I held the rear of the frame rigid, set the front crossmember on a single pivot point, and clamped a 6" long arm across the front frame rails. Load the arm with nuts and see how much less the frame twists with each additional bar.

Mike P

 

[SuperBuickGuy]

When I was adding structure to my car, I built a little balsa model of the frame and twisted it with an arm and some hex nuts. I held the rear of the frame rigid, set the front crossmember on a single pivot point, and clamped a 6" long arm across the front frame rails. Load the arm with nuts and see how much less the frame twists with each additional bar.

Mike P

my hoop is welded to the top of the rail about where your model's is.... it's about 3" off the centerline of the seats - thus running your door bars like you've got would put the door bar at nearly the middle of the seat.... which is why I haven't run door bars yet.

 

[Twin_Turbo]

When I was adding structure to my car, I built a little balsa model of the frame and twisted it with an arm and some hex nuts. I held the rear of the frame rigid, set the front crossmember on a single pivot point, and clamped a 6" long arm across the front frame rails. Load the arm with nuts and see how much less the frame twists with each additional bar.

Mike P

your car in your avatar??

 

[phantomjock]

I was bored and got tired of thumbing for this shot...


Guess I need to compare to SCCA and NASA to make sure its meeting current GCRs.

Cheers - Jim