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Roll cage - Sizing and walls - SCCA/NASA/Rally/NHRA differences


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Well.. I'm getting ready to start buying the materials for my half cage.. and I'm running into a slight problem...

 

Here are the required roll cage tubing requirements : (all mild steel)

 

Rally America - Section 5.5 -

DOM - 1.75 x .095

 

SCCA - Section 9.4.1 (appendix G) -

DOM - 1500-2500 pounds - 1.5 x .095

Over 2500 pounds - 1.5 x .120 or 1.625 x .120 or 1.75 x .095

 

NASA CCR - Section - 11.4.7 -

DOM or ERW - Under 2000 pounds - 1.5 x .120

2001 - 3500 pounds - 1.75 x .120

 

NHRA - NHRA's FAQ website

DOM - 1.625 x .120

 

Hmm.. seems like if I ever want to explore and have a fun time in any of the sanctioned events.. I should probably go with a 1.75 x .120 DOM mild steel for any event!!??!

 

My car is not a dedicated car to any sanctioned event.. just want to have fun.. but be SAFE

 

What are most of you guys running?!

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DOM Tensile Stength = 70,000 psi

Diameter (in) Thickness (in) ID (in) Cross Sect. Area (in^2) Tensile Strength (lbs) Weight (lb/ft)

1.75 0.125 1.50 0.64 44,668 2.169 lb

1.75 0.095 1.56 0.49 34,575 1.596 lb

1.50 0.120 1.26 0.52 36,416 1.769 lb

1.50 0.095 1.31 0.42 29,352 1.426 lb

 

Wow thats a big difference in weight!! Looks like roughly 40 linear feet of 1.75 x .125 will weigh about 89 pounds versus the .095 wall.. which is 63 pounds!

 

blah

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  • 2 years later...

Alrighty.. I found some conflicting information. I can assume this is the difference from a roll *bar* vs roll cage rules?!

 

SCCA - Solo II rules 2011 - Appendix C

2. The size of tubing to be used shall be determined on the

basis of the weight and speed potential of the car. The following

minimum sizes are required required and are based

upon the weight of the car without the driver.

a) Over 1500 lbs.-min. of 1-1/†2 o.d. x .120" wall or 1-3/4"

o.d. x .095" wall

B) Over 1000 lbs.-min. of 1-1/4" o.d. x .090" wall

c) Under 1000 lbs.-min. of 1" o.d. x .060" wall

 

SCCA - GCR 2011 - Appendix I

2. Minimum tubing sizes (all Formula, Sports Racing, GT, and

Production Category automobiles, and all automobiles registered

prior to June 1, 1994) for all required roll cage elements

(All dimensions in inches):

Vehicle Weight Material

Without Driver

Mild Steel Alloy Steel

Up to 1500 lbs. 1.375 x .095 1.375 x .080

1500-2500 lbs. 1.50 x .095 1.375 x .095

Over 2500 lbs. 1.50 x .120 1.50 x .095

1.625 x .120 1.75 x .095

 

Im a bit grumpy because I just picked up my main hoop today.. which is a 1.5" x .095" tube. The plan I have is listed below. My goal was to maintain a street car and aim for Street Modified or Street (Open) in the SOLO division. It seems.. maybe I should sell my current hoop and go with a thicker tubing?! Or would I be OK running this tubing based off my plans.

 

 

Main hoop, rear attachment mounts, x-style door bars, main diagonal, horizontal harness bar and dash bar. 8 points in total. NO a-pillar bars or roof bars for road use.

DatsunCage2.jpg

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