Cage Material per Appendix I

[darthmonkeyIT]

Greetings.

Technical question regarding adding required cage material to a pre 2003 cage.

My current log book is dated 1999 and the cage was installed before then. Exact date unsure. Per the 2006 rules I need to add a door bar in either a "X" pattern or NASCAR side bars. I am adding NASCAR door bars.

My question is, my cage is ERW and per the note in section 9:

Cars registered before 1/1/08 may continue to compete with their previous roll cage as specified in Appendix I.
Cars registered as Production class cars prior to 1/1/08 may continue to
use their existing roll cage per Appendix J.

Per 9.F.1:

Seamless or DOM mild steel tubing (SAE 1020 or 1025 recommended) or alloy steel tubing (SAE 4130) must be used for all
roll cage structures. Alloy and mild steel tubing may not be
mixed. ERW tubing is not allowed.

Adding the new door bars, can I still use ERW or do they have to be DOM? I would prefer to match material for welding purposes. Side note of ERW being a heck of a lot cheaper for about the same material effectiveness with seam welding equipment these days but

To mention my cage is over size requirements. I weight well under 2700# and have 1.5" OD x .120" wall tube.

Thank you!

-Sean

[Matt93SE]

The alloys used in DOM and ERW aren't any different, the DOM starts as ERW and just has the mandrel drawn over it afterwards (among other tiny things..)
But I wouldn't be worried about chemistry when attaching ERW to DOM.

Since ERW is specifically not allowed anymore, I would use DOM and call it a day.

[DoubleXL240Z]

What he said!!!!^^^^^