I am in the market for a harness bar but my understanding is that a potential hazard when a harness bar is installed without a roll hoop. If your roll your car you can suffer a spinal compression injury. Can someone clarify this point. Also, are there harness bars out there that are also a roll hoop?

Thanks in advance.

 

GOOD question, and I'm glad to see someone asking about it before spending any money... What I'm about to tell you is my opinion, and that of many people I've discussed this with, however, to my knowledge, there has not been any research into it...

I do not think a harness bar or harnesses should be installed without a roll bar

The theory: Harnesses increase your ability to drive the car faster. Since you no longer have to exert energy to hold yourself in the seat, you can concentrate on other things. That all sounds well and good, and desired, but that increased speed also increases the risk that if something goes wrong, its going to go wrong in a bad way.

Roll-over If on a road course, chances are the roll-over will be the result of sliding off track sideways into dirt or grass and the wheels dig in, the momentum carries the car onto its roof. More than likely in a low-speed roll- over there would be no ill-effects from the harnesses - I imagine the roof is strong enough to support the car... but in a high speed roll over, the car could become airborn and land on its roof - this is where the risk is. Strapped in, your body will not move anywhere... you'll have a helmet on, so there will most likely be only about 2" between your helmet and the roof. It doesn't take much of an imagination to see that if the roof colapses, what the consequences might be without a structural roll bar. And don't think it can't happen at an autocross... especially with today's tire technology and faster courses - it does happen.

I view using stock seat belts in your street car on track essentially as a type of speed restriction. You will subconsciously not go as fast if you aren't strapped in tight - and since we aren't talking about timed events - that shouldn't be much of a problem.

If you are going too fast for your stock belts to do their job, then its time to invest in a roll bar, plain and simple.

 

Well Put Stacy!

Get a roll bar! Every Z ought to come from the factory with one. the TRACK model ought to have one from NISMO.

It only takes 1/10th of a second mistake on the track at speed to end up on your head. Listen to Stacy.

A Kirk roll bar has been the best value Z modification I have made for HPDE use.

I will add one suggetion to Satcy's excellent position paper on this subject.

Don't forget to pad the roll bar. I went to see a HPDE participant in the hospital with a bad neck injury when his car rolled and his helment hit the unpadded roll bar. JC Whitney has a nice package the includes roll bar padding and a lace up black vinyl cover to make it look sharp for daily street use.

 

Good point tomzz ... but don't waste your money on normal foam padding... it will do nothing to protect you in the event of an impact. Buy the good stuff, the SFI stuff from somewhere like www.racerwholesale.com or the like. It does a MUCH better job in absorbing and dissipating the force than the normal foam rubber.... oh yeah, and it is IMPERATIVE that you have padding especially on the street, when you aren't wearing a helmet.

-Stacy

 

Great.. thanks for the info.

 

If you have everything in your sig on your car, I would run out and get a roll cage immediately!

There are several of us Z'ers that, combined, have run hundreds of events without incedent sporting a harness bar w/o hoop. Almost all of us are running R-compound or Hoosiers, and and at least one of our crew is an former IMSA driver and is amazingly fast. Its possible to run safely without one, but having at least a hoop is prefered. We've had this conversation before, but I'll throw the other opinion out here for completeness.

 

I should be biting my tongue, BUT.......

By amazingly fast, do you mean being faster than a well driven Porsche GT3 on Hoosiers?

 

So is it unsafe to just get the harness bar? I am trying to decide if I want the cage or the harness bar.

 

A harness bar or a properly designed rollbar/cage are required if you plan on using a 5 or 6 point harness. Porsche Club of America requires a 5 or 6 point harness with either a harness bar or a roll bar to run their events at Road America. I'll put my faith in PCA's 40 years of experience in running HPDE's for their recommendations/requirements.

Most, if not all, rollbars require compromises for daily street use that a properly designed harness bar won't.

I chose a harness bar, as it fulfills MY needs.

 

I think you'll find that if you ask 5 different people, you'll get 4 different answers - there should be enough information above for you to make an informed decision.

I'm of the opinion that if you're going fast enough to need a harness bar, or... if you ARE fast enough that you need harnesses and a harness bar IN ORDER TO go faster, then you are fast enough to warrant installing a 4-pt roll bar.

Under NO circumstances shoud you install harnesses without a harness bar, the real debate is whether or not that harness bar deserves roll-over protection or not.

 

Most, if not all, rollbars provide roll-over protection for daily street use and track/autocross use that even a properly designed harness bar won't

You MUST consider harnesses/roll-over protection a package deal. Harnesses/race seat/HANS-type device/roll-bar with harness bar...etc, etc. If you don't have the whole package, it creates new problems.

• Harnesses w/o head & neck restraint: potential for basular skull fracture
• Harnesses w/o roll bar: no room for movement in case of a roll-over
• Harnesses w/o race seat: straps not staying in place, reducing effectiveness
• Roll bar w/o harnesses: too much movement, potential for impact with roll-bar

But you also must consider what type of event you're running in. An HPDE, run properly, is non-competitive, educational, driven at no more than 8/10ths... which should be well withing the limits of standard safety equipment, and still be exhilarating and fun... We all know that when you get out there, especially without an instructor, things change a bit... but if you're smart, you'll keep youself in check. If you KNOW you can't keep yourself in check, then you owe it to yourself to at least protect yourself as best you can.

 

it's Safety Equipment. How much do you value your life?

+1! for Stacy's Comments....

There are always tradeoffs when deciding on which type of harnesses/seats/rollbars... don't let cost be an issue. Always strive for the best you can afford. This goes for Helmets too.

 

timely discussion - I have some questions. Quick background:

I autox every weekend I can, and probably do 3-5 track events (PDE type) a year. At a recent PDE I realised I was using the steering wheel to keep myself in place, and am seriously considering a 5 point harness for next year. I think it will help my autocross, and make me safer on the track. My questions:

1 - what are we talking, cost wise to install the recommended from this thread (harness/harness bar and rollbar) ? $100 ? $1000?

2- recommendations on manufacturer/purchase site? Group buy, anyone?

3 - what's the difference between a roll hoop or a roll bar? Anything? Same thing? Relative advantages of each?

I think that my chances of rolling, outside of serious mechanical failure are slim. I push it in autox, but am not going fast enough, and on the track I push it but am well within (IMHO) safety zones. I am not the type to cut corners where my BRAIN is concerned, but I am not made of money either.

Thanks for your answers!

 

If you do decide to go with the harness bar, I am selling one in the classifieds.

 

OK... lets start with 'using steering wheel to hold self in place'... this should be a STRONG indication that you JUST might be going pretty fast. If its not blatant (i.e. if you're not slamming youself into your door and tranny tunnel), and you have leather seats, maybe some simple cloth seat covers for autoX/track will help... But basically, whats happening is kind of a 'physical check.' The theory is that you subconsciously won't go too fast. I will concede there is a fine line here, covered by some grey area... but I think the theory is sound. Lets look at what will happen if you install harnesses only:

Your body will be strapped in and secure, though still not completely until you add race seats. This will allow you to use more energy driving the car as opposed to holding youself in place. Sounds very appealing doesn't it? It will increase your confidence, allowing you to increase your speed. (Keeping it short) you will be faster, the g-loads will increase, your whole car, especially your tires, will be working harder. (I hope you can see where I'm headed here.) Soon, you're gonna want (actually, think you need is a better term) stickier tires because your current tires will lose their grip more quickly now that they are working harder. See how quick you get into the 'ok, now I'm fast enough that I might roll' scenario?
to do it right, probably closer to $1500 for seats, harnesses, head & neck restraint (cause chances are, that airbag won't deploy far enough out if you're strapped in by the harnesses), and 4-pt or better roll bar.
Custom is the better way to go. They are generally safer, can be designed to interfere the least with seat travel, etc. and can be fit much tighter to the specs of the car
A roll hoop, is generally a non-functional show piece, usually non-structural. A roll bar needs to be bolted and/or welded to the frame or unibody in at least 4 places, creating a very rigid structure that will hold many times the weight of the car. There are different specs for different organizations, SCCA is the most respected and most referenced. Tubing size differs based on weight of vehicle, etc, etc. Most roll bars incorporate a horizontal bar used to either mount or guide harnesses for the proper position relative to the driver.
You don't need to be going fast to roll your car... certainly, the faster you are going, the more damage it will cause, but a car can roll under the right circumstances going less than 20mph, especially if you go off track on a road course. But it CAN DEFINATELY happen at an autoX as well... I've seen video. Combine sticky tires with just the right toss of the car, and over you will go.

 

In my opinion you should not even be out on the track without the proper safety equipment. I know that we all started out in our stock Zs, but after doing this for a year or two I have seen some things. It is not worth the risk of what one little mistake can do to you, not to have the proper safety equipment. I've said this in another thread...Safety mods snowball into one big package because you really shouldn't use one thing without the other. This package includes, but is not limited to...

Roll bar (4-point at least)
Roll bar padding
5 point harnesses
Race seats
GOOD quality helmet
Nomex clothing
HANS device (or at least a neck brace)

Here is my theory for safety gear...If you were going skydiving and you had to bring your own parachute, would you go to Wal-Mart or Ebay and buy the cheapest parachute you can find? I know that I would find the best parachute on the market and pay whatever it costs. If I didn't want to or couldn't pay that much, guess what, I'm not going skydiving.

 

I got the autopower 4pt roll bar on order so that I could use a harness.

I plan on using the stock seats because I like having the side impact bag for my daily driving needs. Now, I haven't fit this up yet, so it hasn't been determined whether the stock seat works well enough with the harness.

I haven't purchased the harness yet, but will look into the 4pt or 5pt shroth (as highly recommended by others). Now, can you guys elaborate on why one would choose a 4pt vs. a 5pt harness? There's not that much of a difference in cost, and I'm thinking the 5pt would require construction of custom mounting point.

I don't plan to race competitively...just DE's and daily driving, so compromise is key. I don't think I'll be hitting 130mph in this car, so will a 4pt suffice?

 

wel... if you're goign to mount the harnesses correctly, you should be welding plates to the frame for the harness eye bolts ANYWAY.. so adding one more eye bolt underneath the driver seat shouldnt be too much more labor than the other two..

4 point Cam locks are fine (imho) and better with the stock seat. i.e. so you dont have to jerry-rig a side submarine belt or a Y setup for your crotch.

the stock seats with harnesses are ok.. its just where the top shoulder harnesses come in. i'd suggest you run it thru the headrest loops rather than around it cuz depending on how big you are, those belts sometimes might slip off the top of the shoulder.. (not me, small chinese kid... but on big white people with larger upper torsos)

fyi: Sparco belts = Schroth belts if u cant find any readily available schroths...

 

This debate is just as heated as whether to run them or not at all...

If you're gonna run harnesses... WHY NOT USE 5-6 PTs ?!?!?!?!?!? ESPECIALLY if the cost is about the same. Take a second to think about how harnesses work (or at least are supposed to work.) :

You sit down, you strap the lap belt & sub strap on, tighten them down good, then you tighten the shoulder straps down REAL good... now what do you think will happen when you tighten down the shoulder straps without using an anti-sub belt? Thaaaaats riiiiiiight... the lap belts are gonna ride up unless you don't tighten the shoulder belts all the way. HMMM but that doesn't sound very safe you say! (And people wonder why the Triangle Z Club/Tarheel Sports Car Club doesn't allow 4-pt systems.)

Having said all that, the proper way to mount a sub strap is for the eye bolt to be placed (if I'm not mistaken) within a couple inches of the body's vertical center-line, with the strap NOT wrapped around anything... this is why proper race seats have a slot for the anti-sub strap. THAT brings us back to having a package set-up... technically, you shouldn't run a sub-strap with stock seats unless you're willing to cut a hole in the bottom of it. Now, there are ways around it, as with a 6-pt system where the straps form an inverted V shape and mount to the sides, most agree that its ok to 'sit' on these straps... but ideally, it would be run through the same slot in the seat of any race seat.

From a club standpoint, we've seen nothing but problems with Schroth belts... they are usually too narrow, and they are almost ALWAYS mounted improperly. I'm not sure if this is because of who's buying them, or their mounting instructions, but we cringe every time we see Schroth belts at our tech inspections. www.racerwholesale.com usually has the best prices on harness systems from G-Force, Simpson, and Sparco... I'd recommend them.

I know you guys are tired of reading my rants... but as you can tell, I'm very passionate about this subject

 

Yes... PLEASE don't jerry-rig anything concerning your safety