Roll Cage questions

#1

All you Racer’s out there, I have a few questions regarding a NASA legal cage for a SPEC car. Who’s the best person to ask?

• Is there any benefit in getting it all done in 1.75 x .120 DOM tubing vs the legal 1.75 x .095 DOM? Will having the extra thickness and and weight be a detriment towards the balance of the car?
• The foot protection bars, can they be smaller tubing or should they be the same size at the rest of the cage?
• Is a diagonal bar better than a straight bar in the Halo?
• Yes, I am getting Nascar bars on the Driver’s side, and assumed i’d do the same on the passenger’s side… Is there a pro or con for NASCAR bars on the Passenger’s side?
• Is there anything else I should be aware of?

#2

the only thing i can contribute is that when it comes to cages, all tubing should be the same size, otherwise you run into weak points. At least this is what my cage builder, TC Design, said.

As for thickness, i have seen these cars bashed up pretty good with all kinds of cages, thick and thin, and honestly, i would go for the lightest cage possible. I have a 1.5" cage but i am not sure on thickness. The cage is very light and plenty strong.

Things to think about

#3

Boy, that’s a loaded question on this board. :laugh: I’m not, but what the heck…

[quote]• Is there any benefit in getting it all done in 1.75 x .120 DOM tubing vs the legal 1.75 x .095 DOM? Will having the extra thickness and and weight be a detriment towards the balance of the car?[/quote]It will be stronger, but heavier. It will affect balance in that the amount of ballast you can move around and be at minimum weight will be lower.

[quote]• The foot protection bars, can they be smaller tubing or should they be the same size at the rest of the cage?[/quote]Not worth the weight savings going with a different bar size unless you are really intent on having a true dead pedal.

[quote]• Is a diagonal bar better than a straight bar in the Halo?[/quote]Structurally, probably. I went with a straight bar over the tunnel so it wouldn’t impact my head room or that of a potential passenger.

[quote]• Yes, I am getting Nascar bars on the Driver’s side, and assumed i’d do the same on the passenger’s side… Is there a pro or con for NASCAR bars on the Passenger’s side?[/quote]Nascar bars will be heavier than the minimum requirements. I installed them for passenger safety for those rare occasions when I can get Skeen in the right seat (or my wife can get me in the right seat).

[quote]• Is there anything else I should be aware of?[/quote]Yes, you will get conflicting opinions on each of the foregoing points. Listen to those other people.

#4

I don’t know much about cage design so my ability to help is limited.

Re. NASCAR bars on the passenger side. If you can save some bucks by doing a decently gusseted X brace on the passenger side, I’d consider it. Of the various ways your car is likely to die, getting tboned on the right side while you have a passenger you’re emotionally attached to, isn’t in the top 10 of most likely.

#5

[quote=“Ranger” post=67369]… while you have a passenger you’re emotionally attached to…[/quote]I didn’t say I was emotionally attached to Skeen. I just can’t risk hurting him and getting beat to death with a guibo by his fanboi SE30 guys.:wink:

#6

thanks guys,
i’ve decided on 1.75 x .095 tubing, Nascar bar on drivers side only, Diagonal halo Brace, Xbar on rear down tubes which attach to the trunk flor, and Foot Saver bars the same size as the cage.

#7

Be sure your cage builder has read the new rule this year for the horizontal harness bar.

The front cross bar should not be something you can potentially hit your legs/knees on.

Helicopter tape your door bars once your done painting or you’ll scrape it off getting in and out over time.

Make sure to consider drivers bigger than yourself (to help with future resale) when laying things out.

#8

Anybody have an opinon regarding X bar between the down tubes. Are they necessary for a spec car? Do they add too much weight, shoulld i just have a single diagonal?

heres where im at at the moment.

i have another question regarding door bars also…

#9

[quote=“jlucas” post=67372]Be sure your cage builder has read the new rule this year for the horizontal harness bar.

The front cross bar should not be something you can potentially hit your legs/knees on.

Helicopter tape your door bars once your done painting or you’ll scrape it off getting in and out over time.

Make sure to consider drivers bigger than yourself (to help with future resale) when laying things out.[/quote]

Thanks for the advice, whats the new rule for the harness bar, I looked at the CCR and didn’t see any updates.
Re the dash bar, has anyone ever run it between the steering column, and the bracket it mounts to on the dash?

#10

Found it:

15.6.23 Shoulder Harness Bar
The shoulder harness bar shown in the cage diagram as bar “H” – “G” must meet the
minimum dimensions required for the cage design for the specific vehicle. The bar must
intersect the required diagonal bar, but need not remain in the same plane as the main
hoop (e.g. May bend aft-ward to allow more seat room behind the driver and /or
passenger seat(s); as long as it intersects the required diagonal). The harness bar need
not intersect the main hoop at any specific location (vertically), however the bar should
be installed horizontally (parallel with the ground).