Racing harness mount location

[Jonathan O'Hara]

From finished build pics it seems like a lot of builders who are running racing harnesses are mounting the upper shoulder straps to the bar directly behind the seats.

Is that right? And if so, is it safe?

I thought that the rear mount for the shoulder harnesses should mount +/- 20 degrees from the top of your shoulders? (e.g. https://grassrootsmotorsports.com/articles/strap-how-properly-install-racing-harness/ or http://www.speedhunters.com/2014/06/takata-ask-the-expert-answers/). I I though this had something with in an impact you want the straps to pull your body back into your seat, not down and compress your spine.

I think the bar behind the seats would be a lot steeper than - 20 degrees.

I've currently got mine tied to the rear-most horizontal bar that runs parallel to the engine. This means the straps run pretty much straight back. My harness just reached far enough. I do worry a little about the harness running over top of the engine and tying into a bar that can get a little hot from the exhaust manifold.

Am I missing something, being paranoia, or both?

Thanks for any insight!

 

[Waterdriver]

The bar directly behind the seat is the correct mounting location for the shoulder harnesses.
You are correct in that the increased angle is of concern.

I'm working on getting my harnesses and seat in now and will be taking some measurements.
I'm running an aluminum seat and have it as low as it can go. Seat just clears the 5th belt (crotch belt) bolt head. So I wonder if I'll be in the +/- 20 degree range or not, being 5' 10".

As a safety concern, I dont think you'll want your harnesses running over the top of the engine. I know at a track inspection it would fail. Most likely would fail in a State inspection as well.
In the case you had an engine fire, you'd lose your shoulder harnesses.
Not telling you what to do by any means. just food for thought.

 

[ctuinstra]

The holes in our seats that the straps go through keep it from compressing the spine. It's not going to compress anymore than the height of the holes. I believe what they are referring to are short or open seats where the angle between your shoulder and the mounting point isn't greater than 20 degrees. If you are much taller than the holes in the seat, it's not going to matter where you tie the straps, it's still going to compress your spine. The only exception to this would be if the seat itself were to collapse, but that is unlikely. And if it's that bad, you probably have other things to worry about, such as if you have life insurance and your will is up to date.

Funny things is I've seen many episodes of Roadkill on YouTube that they have their short old-car seats with modern race harnesses strapped to the floor behind the seat. That is a big No-No!

 

[Briann1177]

This reminds me of Cleetus McFarland. He's super tall and his shoulders come way above the openings in his seats in Leroy. Doesn't seem to be an issue at the track.

There are too many different body types, not enough seat variety for those body types, and way too much theory and science behind the correct usage method for it to be practical or realistic.

 

[Jonathan O'Hara]

The holes in our seats that the straps go through keep it from compressing the spine. It's not going to compress anymore than the height of the holes. I believe what they are referring to are short or open seats where the angle between your shoulder and the mounting point isn't greater than 20 degrees. If you are much taller than the holes in the seat, it's not going to matter where you tie the straps, it's still going to compress your spine. The only exception to this would be if the seat itself were to collapse, but that is unlikely. And if it's that bad, you probably have other things to worry about, such as if you have life insurance and your will is up to date.

Funny things is I've seen many episodes of Roadkill on YouTube that they have their short old-car seats with modern race harnesses strapped to the floor behind the seat. That is a big No-No!

Good point, that make sense about the openings in the seat and it preventing spine compression, as opposed to short/open seats. Thanks ctuinstra! I'll happily tie into that bar behind the seat!

 

[Jonathan O'Hara]

After this guidance I went out and checked my setup. It turns out that the bottom of the go through holes in my ProCar racing seat are actually about two inches below the top of my shoulders. Admittedly I'm not the shortest person in the world, so that's a point of concern. Even if I was short enough, I'm also not certain there's enough support around the go through hole to rely on the hole as support to prevent the harness from compressing my spine in an accident. The seat back isn't solid metal, and feeling around the edges of the holes I think there some metal there but not sure how sturdy it is.

Given these two, I'm thinking of just welding another tube behind the seats at my shoulder level to mount the harness to. I think the bar will have to go in two parts to work around the existing diagonal bar there. Does that sound reasonable?