RS / ST seats with 4 point vintage harness - info needed

[advtracing]

I am looking at putting a set of ST or RS seats (vintage / gts or sim) into my mid 70's r-gruppe wagon . the car has a race rollcage ( with out harness bar ) currently fitted with 4 point race harness THROUGH the seat by the shoulders and down to mount locations inside the rear seat bowls on each side . Now if i add some ST / RS seats i want 4 point vintage harness OVER the top of the seat and down to the existing race mount points but i am wondering if they will side off or if between the head rest bracket will cause a rub from being to close together ?
So who can show me a simular setup that works and user experience ?

pic attached , seat in black , harness in red

[obrut]

John,

Please post a pic of your roll cage - that is what I would be connecting your harness to.

[advtracing]

so here is the current set up with racing harness connecting to the rear seat bowls , i want to run the vintage belts the same way as;
- nz law doesn't like Y belts to one point in the rear tray
- the roll cage (just visible)has a 45deg angle brace so not usable to mount to

[JohnT]

John,

According to the safety 'experts' here your proposed harness mounting is ill advised. As I understand it, anchoring the harness far below the drivers' shoulders has the effect of breaking the collar bones and driving them into the top of the lungs and/or heart. The experts don't put much faith in the seat having the strength to keep the harness at an acceptable height. Because of this, you may not be able to find individual harnesses with sufficient length to even reach your rear seat bowls.

There may be some useful information for you here - SFI Foundation seatbelt paper

johnt

[obrut]

John,

I agree - those mounts are too low. Without seat holes to locate them, I think they your belts will be at risk of slipping off your shoulders the one time you might want them not to.

I also wouldn't trust the head rest (which are only as push fit into the seat back) to locate them.

I would either replace the harnesses with regular belts or add a horizontal bar to your roll hoop and run the harnesses from there.

Ps. Is the roll hoop needed to pass scrutiny at competition events? If not, I would not have one in a street car.

[advtracing]

funny , this set up passes race spec in new zealand but not usa , yet lots of stuff passes in the usa that has no chance here ....go figure. so taking on board everything , contacted the low volume cert guys to action the extra paper work and we will do the proper Y belts off the rear tray.
The roll bar was installed for the targa NZ over here , based on the way i drive best to keep it in place .

[obrut]

Anyone that does Targa NZ with that roll hoop is a braver man than me!

[Bobs 67S]

John
can you add a short strap brace between the hoop and cross brace. Something that would bolt in.

[advtracing]

no , if i did this i would need the cage to be re certed up it's current low volume cert for road use

[advtracing]

Update - i am going with Y harness to the rear tray and get my engineer to cert it