SPEC legal Roll Cage Questions

[condor]

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?

[cosm3os]

The rules are your friend, and the first think you need to know is "what class?" as some classes have specific rules relating to cages or accessories you will want your cage builder to include.

 

All I'll say is dont skimp on foot protection.

[RJ's325ITS]

See my answers in your post bellow, and GL with the cage

 

 

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?

 

Bending it will be harder, depending on your design all that extra weight up top will hurt you, remember you want as much weight in the middle and as close to the ground as you can. If properly built the extra thickness will not add strength.

 

• The foot protection bars, can they be smaller tubing or should they be the same size at the rest of the cage?

 

you do not want to cheap out on this, most front accidents end up with one of the front wheels folding down under the car, crushing the floorpan around your feet, and yes it has to be the same thickness unless specified other wise. I.E. reinforment bars do not have to be the same size.

 

• Is a diagonal bar better than a straight bar in the Halo?

 

If you are referring to the "sunroof bar", is better to do a diagonal bar to crate a node at the main hoop and A pillar

 

• 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?

 

you are adding unnecessary weight, do a single X on the passenger side, use the weight you save to add ballast, install your cooler there if needed.

 

So NASCAR bars are the worse ever, remember that when you bend a tube you stretch it and make it weaker, thus nodes where bends are; if you are doing and S type of NASCAR door bar "you are crazy". I hope is the true NASCAR design where you have 3 bars running horizontally with 2 inwards bends making them in a shape of a C, with 2 sets of 3 short bars tieing them together.

 

• Is there anything else I should be aware of?

 

360* welds are a must, where the tubes tie to the floor those plates should be tie to the chassis in at least 2 planes, lots of nodes, lots of X's

[TurboShortBus]

• 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?

1.75" x 0.120" DOM is about 2.25 lbs/foot. 1.75" x 0.095" DOM is about 1.80 lbs/foot (20% lighter). Measure your amount of tubing and see what the weight difference is. If you might need ballast in the car anyway, then you might as well use the thicker tubing. Nobody here is Sebastian Vettel; we are amateurs on track with other amateurs. Protect yourself accordingly, since you still have to be able to work on Monday.

 

• The foot protection bars, can they be smaller tubing or should they be the same size at the rest of the cage?

Per my interpretation of the CCR, the foot protection bars are not required, so you can do anything you want. With that being said, what are your ankles worth?

 

 

 

• Is a diagonal bar better than a straight bar in the Halo?

Diagonal anything is better than straight anything. Make triangles, not squares.

 

• 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?

Don't bother on the passenger's side. Extra weight, extra fabrication, and nobody is sitting over there. Make an X (or the single required diagonal) and be done. Don't get me started on NASCAR bars being in compression in a side impact vs straight bars being in tension; Google it. My side bars will be straight (2013 Aussie V8 COTF style), with the seat moved inboard.

 

• Is there anything else I should be aware of?

Always.

 

Beware of garbage welds. Don't do them yourself just to say you did them yourself if your work is junk. Additionally, now is not the time to buy a flux-core MIG from Harbor Freight to see what you can do. When in doubt, hire it out.

 

Mark