DragStuff

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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

Those front end down bars aren't part of the 8.50 cert, the inspector won't be checking their size or thickness. It's up to you what you want to use. In fact, my old sportsman cage setup didn't even have them and it certed 8.50 NHRA twice, so it's up to you. I would recommend them however, I was having some issues with flex on my old setup.

I don't believe 25.5/25.3 or 25.2 "require" them either, now of course in regards to chassis they have their place no doubt.

Thank you very much

We use 1 1/2" for the forward engine compartment bars. We use chromoly only, can't remember if we use .058 or .065...thinking we use .058.

I just installed a 12 point cage that was bought from jegs and those bars that come in the kit were 1 1/4",contrary to what alot of people think the chassis instector only cares about the tubing that protects the driver,our chassis inspector said if it is in front of the a-pillar or behind the main hoop it is not really his concern,except for special circumstances where your feet are in front of the a-pillars or the driver location puts him under the main hoop then those areas need to be protected and inspected but that is more in the faster certs.
Most dont know but when you buy a SFI certification for a chassis it is not the whole chassis front to rear it is only from the main hoop to the a-pillars,doors and floor so the rest of the chassis is for the installer to design build