View Full Version : 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
TheYellaBrick
03-02-2010, 09:12 AM
??? What is your exact question ??
Do the down bar tubes need to be 1 5/8 x .134 wall tube to get an 8.50 cert on the chassis?
FullTimeRacing
03-02-2010, 12:25 PM
you need to hit the rule book for that.
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
gnsrule
03-02-2010, 01:43 PM
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
Craig, Thank you for the reply :wink:
promod45
03-02-2010, 04:15 PM
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
TheYellaBrick
03-02-2010, 09:45 PM
Anything outside the cage is strictly for chassis stiffening. Nothing to do with protecting the driver.
zipper06
03-04-2010, 08:12 PM
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
Zip.
Anything outside the cage is strictly for chassis stiffening. Nothing to do with protecting the driver.
doesnt the back bars the ones that go to rear frame, offer support and has to be at least 1 5/8 and be within 5" from top of main hoop ?
promod45
03-05-2010, 05:43 PM
they can be what you want i have done some in smaller tubes but then you need more bracing, but from roll bar back its not included in certifing a car, they are only concerned with the part that protects the driver area, if you ever get a chance to see a speck book you will see no bars behind roll bar..
zipper06
03-05-2010, 08:53 PM
they can be what you want i have done some in smaller tubes but then you need more bracing, but from roll bar back its not included in certifing a car, they are only concerned with the part that protects the driver area, if you ever get a chance to see a speck book you will see no bars behind roll bar..
No true, the rule book clearly states that the down bars and support bars bhind the main hoop have to be too spec., shown in the 2009 rule book pictured below. Shown as D" and B"
Zip.
http://img.photobucket.com/albums/v515/zipper2/cagebars.jpg
coolracing
03-14-2010, 08:09 AM
they can be what you want i have done some in smaller tubes but then you need more bracing, but from roll bar back its not included in certifing a car, they are only concerned with the part that protects the driver area, if you ever get a chance to see a speck book you will see no bars behind roll bar..
No true, the rule book clearly states that the down bars and support bars bhind the main hoop have to be too spec., shown in the 2009 rule book pictured below. Shown as D" and B"
Zip.
http://img.photobucket.com/albums/v515/zipper2/cagebars.jpg
He is talking about bars from the A pillar bars to the front stub...