Have an appointment to have a 10 point cage put in my `Cuda.
DOM 1-3/4" tube
I want swing-out bars on both sides since it will probably see limited street use in the future.
It is being bent on location,NOT a kit. Bars will go between windsheild and dash as tight as possible to the pillar.
I think the rear struts should go to the shock cross member{coil-overs}.

1st experience letting ANYONE touch my car in 37 years. current rollbar I put in in 1986.

Opinions/Advise???

Thought cage could be 1 5/8" tubing

Why 1 3/4"?
Roll cage right?
I would go 1 5/8"

Another thing to think about is going to Chromoly, the cost between DOM and Chromoly is negligible. Yes you have to TIG Chromoly so that might play into it.

To make the bars as tight as can be will be pretty difficult. Without cutting the car it is dam hard to weld the joints on the roof line completely.

You might be right.

Haven`t discussed with him yet. I`ve seen kits both ways.
1-3/4' was an assumption,probably a wrong one.
Chromemoly is probably not an option.but I will ask him.
1-5/8' would be nicer.

Weight difference between tubing for reference

1 5/8 x .083 is 1.367 pounds per foot

1 5/8 x .120 is 1.929 pounds per foot

1 5/8 x .134 is 2.134 pounds per foot

1 3/4 x .120 is 2.089 pounds per foot

1 3/4 x .134 is 2.313 pounds per foot

Not a big difference between 1 5/8 and 1 3/4 .120

Bring an NHRA rulebook printout with you.
I'm with you on the cage being tight to the pillars; much more professional and easy to see around.
On my Duster, the forward bars are in the fender wheelhouses so they're not in the engine compartment; they tie to the shock tower reinforcements.

This^^^^^^^^^ make sure you have a copy of the rule book with you, and then verify EVERYTHING before you pay for it.

That includes sonic testing the tubing and verifying the bars are in the correct location.

FWIW when I did my E body Cuda years and years ago we did the a pillar bars tight and through the dash. We also ran the rear bars up against the roof to allow for clearance to the rear seat as well. Since mine was more a street car than racecar, although it ran 9's with the blower motor in it.

There is very little cost difference between DOM and Chrome Moly. CM must be tig welded though. Running the cage through the dash is nice. Makes getting in and out easier. those bars are also tied to the cowl at the windshield base. It also hard to make the dash fit cleanly around the tubes. Who will be doing that? Mine has bars going to the floor and shock mount cross member. The main hoop diagonals tie into the ladder bar mounts.
Doug

My car has an aluminum dash for now.
Eventually I would like something more stock looking, probably fiberglass.

There are construction methods that can be used to get the bars up and out tight. Taking the windshield out can help with getting the A pillar and eyebrow bar or halo in. Don't forget frame ties if they need to be included or up graded. Tight fits and clean detailing takes time. Time is money. If you have to take a rule book along and tell the guy how to do it, are you sure you picked the right guy? He should be telling you.

Mine is c.m. and goes through the top of the dash. Notched dash back around the A pillar bars. We tacked all of the main structure in the car. Then spilt it where the rear portion of the A pillar bars ties into the main hoop. Welded everything up 100% outside of the car except at the split. Placed back in car and welded those two spots.

I used CM years back when it was required to have one.My only regrets are not going through the dash or installing a diagonal bar overhead for a parachute release handle.

Dennis nice to see you are working on the Cuda again. I dropped my Cuda off for a redo last month. I am going with CM. Like others said price difference was minimal.

I will be checking the status when I get home next week.

1-3/4" has 27% more bending resistance than 1-5/8", weighs 8% more.

There are 3 reasons why a cage:
1. pass tech
2. safety
3. chassis response

The same plans are not equally effective in all 3.

I know all about it:

6.0 Cert

We cut the roof off

You can tack it and the current the sill plate outriggers. Drop it down, weld the top and then lift it back up. Good fit is key.
Doug

Serious questions: Do you even own a racecar? Have you ever raced a car?

I missed the ceremony in which you were given supreme authority to approve credentials.
Apparently those comments are both strange and frightening to you.
You're right, I'm 12, and ride a bicycle, which means I must be wrong.
Exactly what part of my remark is error?

Seemed like a reasonable response from an engineering standpoint to me.

Kevin

Some people over think this game and take all the fun out of doing it wrong the first time. Old Poly talks about 10 miles over my head but I’m sure he saves a few guys a few bucks so that’s a good thing.

actually , with (nice) bicycle frames it's similar concerns.
do you use 1"/1.125" tubes or the "oversize" tubes 1.125"/1.25" tubes with thinner butting. Likely you can gain significant stiffness with minimal weight penalty.

Yep, Poly is right. Once one starts thinking like an engineer it's hard to stop. He didn't indicate which choice to make.

His post seems to me to be mostly fact and not indicating a choice, only that there IS a difference. And yes, a cage made to optimize any of the three options would look different for each one.

Strengths of Materials is the one course I use most in my professional and personal life. Ron Apanian should be proud.

R.

My friends B body. Lots of clearance underneath and you don't have to work around a bar in the engine compartment.

A good cage at work. CM - the halo bar deflected about two inches - when the whole car landed on it during the barrel roll. Front supports from the cage to the front longitudinal under the fender. The roof was later cut off and the cage cut out of the car - only bar needing repair was the halo bar.

One place not to be cheap.

True.

Passing tech is the minimal accepted cage structure. Rarely is it adequate or sufficient for improving the car. And there's typically plenty of room for improvement of driver safety.

Safety is a given. We see people walk away from things like hitting the wall at high speed and the Stevie Jackson blow-over. Rarely these days do we see a tube car chassis/cab structure compromised. The structure is stiff and strong. Rule changes usually result from some unusual situation that we don't want to have happen again. The idea is to contain the driver in that protective structure. Recent improvements have been in driver gear - helmets, HANS, padding, shields, restraints. There is such a thing as an unsurvivable wreck. The body can only take so much G-force.

Chassis response/flex or the lack of it, is by design. Added or reduced tubing and tube sizing, bracing, diagonals, slip joints, while maintaining the requirements of the spec, can be used. Proper bracing is a more effective way of stiffening the structure. While they could, I don't know of anyone who uses 1.75" in place of 1.625".