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I am putting a rollbar in my 71 duster built for the F.A.S.T. class. I am trying to figure out the lightest, legal bar I can put in.

From reading the rule book I can run 1 3/4" .083 chromoly bar hoop with same size d/s sidebar, no p/s sidebar and equal sized rear braces.
With a 1 1/4" .065 cross bar.

Anybody ever build a bar like this? Approx. weight? Difference in weight of mild steel?
I have 2x3 frame connectors through the floor that I imagine will give it all the stiffness it really needs, so the bar is really only to appease tech.

Thanks guys.

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The main hoop, drivers bar, and back bars are about 25' of 1 3/4, and about 5' of 1 1/4 for the crossbar.

Weights of round tube - per foot:

Mild Steel .134 Wall D.O.M.
1 3/4 = 2.31lb 1 5/8 = 2.13lb 1 1/4 = 1.60lb

4130 Chrome Moly .083 Wall
1 3/4 = 1.47lb 1 5/8 = 1.37lb 1 1/4 = 1.03lb

4130 Chrome Moly .065 Wall
1 1/4 = .82lb

So the mild steel would be about 65 lbs total, and the Moly about 41 total.

Hope this helps....