roll BAR

[akdg87]

Looking for some insight... I have a chris alston 8 point roll bar kit for my 1955 chevy. I was planning on installing it as a 6 point without the rear struts that would tie into the frame in the bed.

I don't live anywhere near a track (closest one is in Palmer AK and that's a 6 hour drive for me one way, however i do go down once or twice a year). I'd like to be covered for next time i go to the track and just general street driving, they basically said don't come back without a cage or bar.

So i've been studying the rule book and checking out other members build threads. This rule has me perplexed: "All vehicles with OEM frame
must have roll bar welded or bolted to frame" (NHRA 2020 section 4:10)

Initially i thought we would have to weld outriggers to the frame, drill holes and then weld the main hoop and doors bars to those. But reading that rule it doesn't appear so. Anyone ever bolt one in?

-DG

[Overdriven]

A roll bar and possibly even roll cage (been awhile since I’ve looked) can be bolted in to facilitate removing the body from the frame. Also sections of the roll cage can be removable for access, like the front down tubes in the engine compartment. Pretty sure rules for flange thickness and hardware diameter are somewhere in there. There’s also a performance limit to bolt in bars and cages, go fast enough and it’s gotta be welded in.

In your case you’d still need to weld outriggers to the frame. Then add tube on top of the outrigger (a riser) to put a flange at the bottom of the floor. Put a flange on the inside of the floor and have your bar on top of it. Oh and leave enough space for 4 bolts to go through the flange around the bar. I’m not sure if it would be legal to have the flange at the outriggers with a riser on top of it, you always see the flanges sandwich the floor pan.

[regan wilson]

What did it run last time at the track?

[PGSigns]

The requirements for bolting in a roll bar are top of the floor a 6X6 steel plate bolted through the floor to another 6X6 plate. The roll bar is welded to the plates. There are requirements for the bars that make a roll bar or cage up. There are ways to make some of the bars bolt together and there are specifacations for that like for a swing out side bar. One thing that NHRA kind of assumes is that you are working on a car. Trucks take a bit more work. You are going to need the bars going to the back. Regan asked about how fast you went. That will answer a lot of question on what you have to have along with what you may want to do above that to help the chassis work and to allow you to pass if you decide to go a bit faster.
Jimmy

[akdg87]

Originally Posted by regan wilson

What did it run last time at the track?

it was my first time ever on a track and i did a 10.7 at 128. i had to turn the shift RPM way down because it was spinning on the 1-2 and 2-3 shifts. my 60' was a 1.83 (couldn't boost launch)

[akdg87]

Originally Posted by PGSigns

The requirements for bolting in a roll bar are top of the floor a 6X6 steel plate bolted through the floor to another 6X6 plate. The roll bar is welded to the plates. There are requirements for the bars that make a roll bar or cage up. There are ways to make some of the bars bolt together and there are specifications for that like for a swing out side bar. One thing that NHRA kind of assumes is that you are working on a car. Trucks take a bit more work. You are going to need the bars going to the back. Regan asked about how fast you went. That will answer a lot of question on what you have to have along with what you may want to do above that to help the chassis work and to allow you to pass if you decide to go a bit faster.
Jimmy

Thank You; i didn't get the automatic notification emails on the latest two replies (yours and regans) and somewhat forgot about the thread. i just replied with my ET from last fall. I wasn't planning on taking any shortcuts but was just trying to see if there was maybe an easier way to put this bar in. My goals would be a 9.99 since i do daily drive this thing during the summers here (may-september). I just thought it was odd that chris alston chassisworks sent me a kit specific for my truck but also included the 6x6 plates.

[Overdriven]

If you don’t want to install bars in the rear it can be done, just not with the kit you bought. I’m not intimately familiar with the specs listed but the 25series SFI specs listed tell me you basically need a funny car style cage to avoid having the rear bars.

[PGSigns]

The 6X6 plates can be welded in also. To run faster than 10 flat and slower 8.50 you will need a basic 8 point cage. You will have to run bars to the back, the main hoop, a halo bar, the two down bars and the 2 door bars. The drivers door bar can be swing out. Put solid aluminum cab mounts in it. Now if you want to put a cage in it that does not need the down bars you can put a sfi rated 25. style cage in the truck. They still have bars that go to the back they are just lower. The requirements are extensive and there are a lot of bars in it. You can order the specs from the SFI foundation. A well built 8.50 cage will get you to where you want to be and can really aid in tuning for traction and getting rid of flex that can make it hard to control the torque a turbo motor can make.
Jimmy