harness bar: is there a design standard / requirement / rule?

i can't find anything other than "harness bars are dumb".

is there a rule on the use / construction / materials for harness bars, specific to the $2000 Challenge of course but even some general guidance would be appreciated.

This isn't a great answer- I'm not an active racer, but I did read the scca solo rule book regarding roll bars/cages, and there is no mention of specs/requirements for harness bars. Advice I got from the forum was to use the same material/size as the cage structure but that seems like overkill. I went with 1.25x.065 4130, because that's what I had in the shop. I have not had it tech inspected yet. 

In reply to Teh E36 M3 :

I suspect the requirements will be in teh harness section, not the roll bar section. 

Angry, do you have some roll cage tubing? I have several different diameters/wall thicknesses and some 1/8" plate. If you want, I can bring something, but I would need some rough dimensions (length of tube and plate size). Also a welder on site... I think I saw someone post they would have a 110V machine. i could bring my 110v Flux core machine if needed.

Sizes in stock range from 1-1/4 to 1-3/4.

From a corvette forum. Seems to match what little I know on the subject.

Also an artcicle from the home team

https://grassrootsmotorsports.com/articles/strap-how-properly-install-racing-harness/

I will measure the length, but I kept 1 stick of the tubing I used for harness bar on Riggamort. It's "roll bar" spec but might not be wide enough for the corvair. I have padding as well that I can/will bring tonight.

stafford1500 said:

Angry, do you have some roll cage tubing? I have several different diameters/wall thicknesses and some 1/8" plate. If you want, I can bring something, but I would need some rough dimensions (length of tube and plate size). Also a welder on site... I think I saw someone post they would have a 110V machine. i could bring my 110v Flux core machine if needed.

Sizes in stock range from 1-1/4 to 1-3/4.

I'm bringing a Miller 110v welder.  I do not have a generator.

My mustang had eye bolts through the back floor with big washers and passed challenge and scca tech. Not my preferred way, but it worked and I bought it like that. 

It looks like the relavent NHRA section is Section 21 Page 45/46 

The most important passage since it's already been determined that you are required to have it is:

All harness sections must be mounted to the frame, crossmember, or reinforced mounting, and installed to limit driver’s body travel both upward and forward.

So it looks like if you install a harness bar sufficent that it meets those words and your manufactures specified angles or those from NOHOME's Picture you should be okay.   

For sizing there isn't alot of guidance that I could find.  

In Section 21 Page 34 they talk about cars with no OEM floor and the sizes required for harness mounting is: 

a crossmember (minimum 2 inches x 2 inches, .083-inch wall thickness square tubing) must be installed between framerails for proper driver’s seat, seat belt, shoulder harness, and crotch strap installation.

I would consider using NHRA legal 5 point roll bar tube to be extra bestest legal which should be 1.75 x .118 wall Mild Steel.

But it sounds like reinforced floor mounted anchors would be okay

Thanks all, I appreciate the info. ClassicJackets brought material for reinforcement plates and bar, and I have an idea for how to make.

now just need in-date harness.

In reply to Keith Tanner :

What I found was only related to mounting angles and hardware. Weird that it wouldn't specify what they are mounted *to*.  Probably lots of sheet metal mounts out there. 

FWIW when I asked Tom about one for the DSM a couple years ago he told me it had to be welded in & not bolted. Idk if anything has changed since then. 

My harness bar project grew a little. Welded pads that I can bolt it in. Made down pipes that attach to seat belt mounts.