I'd like to get the Schroth Hybrid II 6-point harness and I was researching it and came across this document on Schroth's web site - http://www.schrothracing.com/sdocs/TechTactics.pdf

I came across this, on page 32 of the document:
This throws a monkey wrench in my plans because I don't want to buy a racing seat. Can anyone here with racing experience tell me whether it's okay to use the Schroth Hybrid II 6-point harness with the stock seats? I have a 2003 touring model 350z. thanks

 

...NO, NO, NO...use a seat designed for six point. Most all track groups, including PCA and BMW clubs will not let you run comp harnesses with stock seats.

You are safer with stock seats and inertia belts. Several fatalities were studied which involved 5/6 points with stock seats.

I removed my six points from my Boxster after reading these reports, because I didn't want a comp seat.

If you are a track junky, get the seat. If you are just an occasional tracker....keep inertia belts and stock seats.

 

I had the schroth asm (4 point) and I used them with the stock seat... no problem except "burning" my neck because I was using them trough the headrest.
I still have to drill the seat base (sparco) to put the 6 point... but the seat helped more than the harness except braking.

 

So the Schroth installation document says not to install the 5 or 6 point harnesses with stock seats and you choose to ignore that and ask people on an Internet message board? Do you think any of us know any better then the engineers and bio-mechanics at Schroth?

 

This topic has been covered before. The other BIG problem with using racing harnesses without a rollcage (or rollbar, at a minimum) is that your upper torso is held in place by the belts. This means if the roof ever becomes compromised, both your head and neck are at serious risk. Since head and neck injuries/fatalities are some of the most common in motorsports, why would you risk it?

 

Thanks for the responses.

John, I didn't choose to ignore. In fact, I cited it in the first post of this thread. Here's my thinking for posting this question here, despite the Schroth statement -- tell me where I'm off:

Schroth makes the blanket statement that you cannot use a 5 or 6-point harness in any stock seat. Ok, what about the Porsche GT3 RS stock seats? What about an Elise or an Exige? Aren't these seats okay with a 6-point? (maybe they're not, I could be wrong). My point is, there must be some OEM seats which are safe -- in fact, designed -- to use with a 6-point harness.

If this is true, then Schroth's statement is actually false (it only takes 1 counterexample to prove a statement false). If they had said "no 6-point harnesses with any OEM seats except for these..." then maybe it would be an accurate statement. Another reason I didn't choose to blindly accept Schroth's statement is because lots of aftermarket companies just say this for legal liability reasons. Just like every mod is "for off-road use only".

So I am here asking about a very specific set of seats: the stock leather seats in my 2003 350z touring. If they aren't safe to use, I'd just like to know why. I am learning about harnesses, seats, HANS, etc - help me learn what qualifies a seat as being safe to use with a 6-point harness. Or give me the name of a book to read, or whatever.

And to dkmura's statement about harnesses being unsafe without a rollcage - I've read this harness/rollcage debate for a long time, and this is the main reason I still don't have a harness after driving on the track for a few years. However, I found this on page 32 of the very same Schroth document from my first post:
See why I'm confused? I get conflicting data from different people who know what they're talking about! In any case, I'm not even asking about the harness without rollcage issue - I'm asking about 6-point harness with my stock seats.

 

There's a number of places you're off.

1. Let's say you put these belts in your car and have a wreck on track or even worse, a wreck on the street. The insurance company that has the claim filed against it will inspect your vehicle and note any modifications. In some cases the insurance company will flat out deny the claim if they see any mod on the car at all. In others they will check the installation of the mod with the installation instructions. In this case, because of Schroth's disclaimer, they will deny the claim.

2. You and I have no idea if this type of seat and mounting is approved by Schroth. If you have one of those cars, call Schroth and ask them. You don't so why are you bring them up as an example? Call Schroth and ask if your 2003 350Z stock seats are approved for their 5 and 6 point mounting. Off the top of your head, what do you think they will say?

3. Exactly the point in my original post. Why on earth are you relying on an Internet message board for this type of advice. Call Schroth and ask them!

 

Thanks for the help. So what's my next best bet if I want to keep the stock seats? A Schroth 4-point with the anti-submarine (ASM) stuff?

I'm posting this question on the forum because I like to get feedback from others. I know some people on the forum are full of it, but I've read this forum long enough to have an idea of who knows what they're talking about.

 

that is what schroth suggest.... and you can upgrade it to a 5 or 6 point any time (they sell the squeezeball latch as option)

p.s. looks like tws is going to be crowded

 

I don't know why you insist on a stock seat with competition harnesses. Please pay attention to experienced track folks and either get the proper track seat that has provisions for the shoulder harnesses at the right angle or just use your inertia belts. They are safer when using stock seats........AND if you do get a comp seat please get a HANS device too, what is your life worth??

The GT3s and Lotus's that are listed as exception essentially HAVE comp seats from the factory. They have provision for comp shoulder harnesses and ant-sub belts. ie slots in the seats for these items.

 

Absolutely but again, be sure to follow their installation instructions. Hopefully you'll never need to test it. Good luck.

 

I wanted to post a follow-up to this thread.

I found another harness from Schroth called the Profi II ASM, you can see it here:
http://www.schrothracing.com/store/C...m/profi-II-asm

From the above web page:
The reason they consider this safe to use is because it has the anti-submarining (ASM). Another benefit is they sell sub straps additionally, which makes it a 6-point harness. So if you later get a race seat that is designed for a 6-point harness, you can just buy the sub straps instead of buying a whole new harness.

I called Schroth USA to make sure I understood this all correctly. Thanks to everyone who commented here.

 

good follow up

 

Except many HPDE's now (including Porsche Club of America) don't allow 4 point harnesses, I think either stock belts or 5 pt. and above.

 

Many will except 4 point "IF" they are DOT certified for the make a model. Schroth is one of the few companies that does that with documentation is one of the ONLY companies many HPDE groups including PCA will accept.

 

this is important, and as far as i know, there isn't a 350z application

 

I think the Profi II ASM FE is street-legal, at least according to the web site it is - I'm not sure if that's the same as DOT approved. The street legality had to do with the release button being red, instead of the usual cam lock that you rotate to release the belts.

I'm curious about the PCA rules -- do they not consider whether a 4-point harness has the anti-submarining stuff? (It really is just curiousity, I don't plan to run with the PCA club, I'm just trying to learn more about the subject of harnesses).

 

It has a lot more to do with the car's overall safety system than an individual component. If you have 5 or 6 point harness with no seat integration or roll over protection the basically your body will have no place to go if the roof collapses or the straps may slip off your body's "hard points" and basically will be useless in a front impact.

With a 4 point system tha the danger is a submarine into the foot well or spine compression with a roof failure. A DOT 3 point system is designed to place you to the side in a roof failure and cause you to bend at your hips in a frontal collision. What makes Schroth's different is it allows for the same bend as a 3 point by the impact folds at the top of the shoulder belts.

Overall though is if you are planning to use anything other that a 3 point system in a high speed event, you reall need roll over protection and belt placement aids (seats, or some belt placement straps).

 

Here's a question... as it doesn't seem to have been asked to you yet: Have you asked the event organizers of the event you are planning to participate in if you are allowed to use competition harnesses with stock seats yet? It doesn't matter what any of us think, or event what Schroth says, if the event doesn't allow them.

Determine whether the "event" cares or not first ... then decide what YOU are willing to sacrifice.

• We've already determined that you accept the risks of harnesses w/o a roll bar. That means:
  1. You're willing to sacrifice ideal harness mounting
  2. You're willing to spend/risk more in the long term than risk less/spend more in the short term

I understand your confusion with the info from the various sources... but comes down to the event's rules, then your own personal risk level, in that order.

Can you tell us the exact reasons why you want the harnesses? I ask this in most threads, and I can't say that I've ever gotten a succinct answer. There are SO many variables in play that I don't even open most of these threads anymore, but it is a very important issue.

 

The events I go to don't have any specific rules about this except for convertibles must have roll bars in certain run groups (doesn't apply to me). Oh they do have one rule -- the passenger must have the same harness protection as the driver (i.e., no 4-point harness on driver side and stock belt on passenger side).

Also, I will install the harnesses with a harness bar (such as the Sparco one that is popular). Is there some realistic risk of a properly designed, properly installed harness bar breaking during a collision?

Addressing the no-rollcage issue - see my post above from Schroth's web site (PDF) saying this isn't an issue. I think this is one of those 1% cases that people keep regurgitating on the internet. I could be wrong, but Schroth is the most authoritative answer I have gotten yet.

I want the harness for two reasons, in this order:

1. To hold me in the seat better
2. Safety equal to or greater than stock belts in the COMMON CASE (not the 1% case). Amdahl's law, for the engineers out there. By common case, I mean the common accident case. Of course, the common case is that there is no accident, and this is my first line of protection