Roll Bar specs

[Matt Fredrikson]

I went on the NHRA website and found a diagram and material specs for what they want us to use however they did not mention any weld requirements, or any attachment requirements besides attaching to the floor/frame. What I am wondering is can I make my main hoop bolt to my supports. I would like to have a 4 inch pipe comming out of the hoop at both the top back and front bottom with a plate welded to it as a flange and then attach that with a matching flange to the support. I would use the same specs for that flange as for the floor flange. Does anyone have any experience with this or will it be a weld in place affair only?

[KevinBuckham]

Check out the road racing organizations as there roll cage specifications are generally more precise and sometimes more restrictive.  Ryan Hobbs was working on a cage in his old car and his plan was to make it both NHRA and CACC legal.

They did specify welding current, and type (MIG only), as well as suggested that chromoly cages are a poor choice.

For your specific requirements, I really don't know what NHRA will allow.  I suspect that it will be up to the inspector.  For road racing, they have to be welded in and are often both bolted AND welded down.  Removable sections are frowned upon.

[Scott Girvin]

MIG (GMAW) and Tig (GTAW) welding processes are allowed. Grinding of the welds is not allowed.