Roll Bar/Cage Tubing Material, Diameter and Wall Thickness

[Neil B]

For you track-oriented guys, what tubing material, diameter and wall-thickness did you pick for your roll bar or roll cage? For a 3,000 lb. car, current SCCA/NASA rules seem to require 1 3/4" x .120" tubing regardless of whether it's mild steel or alloy. This is compared to the NHRA spec of 1.75" x .118" mild steel or 1.75" x .083" 4130 alloy.

[SSLance]

The guy that built my 4 point bar made from it from 1.75" OD 0.120" wall mild steel. Said it was good for everything SCCA related up to actually door to door racing (no door bars or front hoop).