Drax240z

Hey all. I am planning on building my self a roll cage shortly, and I need some info on what the SCCA requirements are, as well as the NHRA requirements. What I need to know is required diameter as well as wall thickness. I won't be using chro-moly or anything exotic, just good strong steel. (MIG welded)

I know the main hoop cannot have more than 4 bends, that the mounting points need to be 6"x6" of at least 1/8" steel, etc. I am just looking for info on the bar material itself, as I want to only do this once.

The Plan is for a 6 point cage right now...

Drax240z

That would be great. I heard that S&W uses 1 5/8" mild steel, .134 wall thickness, which exceeds the NHRA requirements. Not sure how they translate to SCCA, but I'm thinking that the NHRA requirements are probably the more strict of the 2...

Any more info would be greatly appreciated.

Drax240z

Hmm, checked into things a bit myself.

1 1/4" Schedule 40 pipe is 1 5/8" O.D. and .140 wall thickness, which meets or exceeds the specifications.

I am not sure how necessary it is to use DOM or ERW tubing however... Anyone?

This car won't see a huge amount of track time, I just want to be able to run without having to worry about the cage.

PS: At what level do they actually start inspecting your cage to see if it meets requirements?

JohnCoffey

Use the pipe they specify. You are building a structure to take a lot of force and protect you from injury, you're not using the pipe to transport fluids.

There's a lot of research and experience behind the rollbar specs in the SCCA's GCR. My suggestion is that you build your cage to those specs and benefit from 40+ years of people crashing sports cars.

Its really expensive to have to cut out a roll cage and weld in a new one. Much more expensive than paying to get it done right the first time.


John Coffey
johnc@betamotorsports.com

Drax240z

All good advice John.

I found that I can in fact get the tubing I need for the cage fairly close to home. (which was my biggest problem, living in a small town) So I am going to go with the ERW 1 5/8" .134 wall tubing.

Thanks all.

JohnCoffey

The real bummer about SCCA's roll bar/cage rules is that they took away the wall thickness break you got from using CroMo. The tubing in my car is 1 1/2" .095 wall, which met the requirements from 5 years ago, and saved 45 lbs!


John Coffey
johnc@betamotorsports.com

Drax240z

How big a cage are you running John, to save 45 pounds? an 8 point, or are you running a full cage, through firewall, etc?

45lbs is impressive savings!

JohnCoffey

I guess my reply got lots in the transition to the new site...

Anyway, my 240Z has a rollbar in it and the weight savings came from the design, the tubing selection, and what material we used for the mounting plates.

I just posted my "ride" on this site and I'll post a shot of the roll bar once I get it scanned.


John Coffey
johnc@betamotorsports.com