what size tubing for down bars on cage?

Old 03-02-2010, 08:37 AM
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al34
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Default what size tubing for down bars on cage?

Hi everyone, I was thinking of adding down bars to my mild steel 10 point cage. The bars would go from the vertical door pilar bar through the fire wall and down to my stock sub frame. My car currentley runs 10.0x times. The cage is constructed of 1 5/8 x .134 wall tube . I would like to use 1 1/2 x .120 wall tube for the down bars, do the down bar tubes need to be 1 5/8 x .134 wall tube to get an 8.50 cert on the chassis? Please help - Al
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Old 03-02-2010, 10:12 AM
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TheYellaBrick
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??? What is your exact question ??
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Old 03-02-2010, 10:45 AM
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al34
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Do the down bar tubes need to be 1 5/8 x .134 wall tube to get an 8.50 cert on the chassis?
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Old 03-02-2010, 01:25 PM
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FullTimeRacing
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you need to hit the rule book for that.
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Old 03-02-2010, 01:59 PM
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al34
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My NHRA rule book does not address those bars and I believe the down bars are addressed in an SFI spec which I do not have that is why I am asking her - Thanks Al
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Old 03-02-2010, 02:43 PM
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gnsrule
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Im not 100%, but I dont belive anyone cares wether or not you even have those bars yet aloone what size they are. When I had my 25.4 cage certed,7.50, all they looked at was the interior CAGE bars.

Craig
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Old 03-02-2010, 03:42 PM
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al34
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Craig, Thank you for the reply :wink:
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Old 03-02-2010, 05:15 PM
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promod45
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He is right the only bars that they are concerned with are the bars around you, the bars behind roll bar and in front of firewall are not even in spec book
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Old 03-02-2010, 10:45 PM
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TheYellaBrick
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Anything outside the cage is strictly for chassis stiffening. Nothing to do with protecting the driver.
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Old 03-04-2010, 09:12 PM
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zipper06
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Agree forward bars are only stiffing bars, nothing to do with the chassis certs., if you are goining to a strut front end then i would use 1 5/8' if it just structial anything works.

JMO

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