harnesses: what works/legal?

nostatic · nostatic's Garage

Are there limits (legal and logistic) on what you can use for seatbelts? For instance, if you were to install a Sparco Torino or Milano, you presumably can run the stock three point belts, or a harness tethered to the rear seat anchor points (and do you have to run a harness guide bar and/or roll bar?). I've also read about the fact that you really need to run an anti-sub 5th belt to keep the belt positioned right.

Any run these seats (or something like it...I'd want an adjustable seat I think)? And if so, is running a harness on the street advisable and/or legal? It would be nice to have a seat with a little more side support than the stock one.

obrut · 08-11-2003, 11:05 PM

As to US legality - I'm a deer with no eyes... (a joke so old it could be carbon dated)

As to usability - one thing to watch for is how high the seat is at the area near your hips. I have Sparco Pro-2000 seats in the race car and the high sides mean that the waist belt of a normal 3 point setbelt sits on the seat sides and about 2" above my thighs/hips - and is thus useless.

Cheers - Ryan

makaio · 08-12-2003, 12:13 AM

Static, I think factory sport seats would be perfect for you. I love mine out of the SC, except they're old and tired. They actually have more lateral support than my Corbeau Forza II's that I replaced them with.

nostatic · nostatic's Garage

actually I found the factory sport seats to be a bit narrow across the shoulders for me. Before I did anything I'd want to find a local dealer that had the seats around so I could sit in them and see what fits.

jakermc · 08-12-2003, 06:20 AM

Recaro SRDs sound perfect for what you want. They will allow you to use either harnesses or the stock belts very comfortably and the seat back is adjustable. This is the set-up I am using.

Harnesses are not legal for the street so keep the stock belts installed. A sub-belt should be a requirement for harnesses. Its a safety issue, without it the lap belt can ride up and do damage. Also be aware that harnesses without a roll cage can be dangerous in the event of a roll-over. A three-point belt is actually safer if you find yourself in this situation.

Vipergrün · 06:51 AM

Actually, Schroth makes a DOT approved harness, and are *street legal*...

http://www.schroth.com/products_en/privat/Rallye_II_III_FE_asm.htm

Jim Richards · 08-12-2003, 07:28 AM

I've heard many people say the same thing that jakermc said...

Quote:

Also be aware that harnesses without a roll cage can be dangerous in the event of a roll-over.

It would suck to be held up nicely by the harness while the roof is caving in on you. Not that it would ever happen...

dotorg · 08-12-2003, 07:37 AM

How strong are the roof structure in the 911's? The car seems built like a tank. Compared to a modern (4000lbs) car, is the 911 more likely to not cave in a rollover, with the more vertical A-pillars and more substantial steel?

I ask because my rule has *always* been not to ride in a car with 4+pt harnesses without a roll bar, but I've got a choice between running lap belts only or 4pt in my 911 until I find a shop to put a roll bar in, and I've yet to decide if the risk of non-racing rollover is high enough versus being t-boned by an SUV with just a lapbelt...

304065 · 08-12-2003, 07:38 AM

Nostatic,

I respectfully disagree with the above posters: if your roof is caving in ( which is not likely, given the structural strength of even an early car) a three point belt is not safer than a five-point, you are not going to "duck out of the way."

Watch this guy in the Subaru at Lime Rock. Nice slow rollover. Centrifugal force and sheer lack of situational awareness keep you from ducking.

http://www.vintagebus.com/gallery/movie/rollover.mpg

If you are driving under conditions where you want the security of a five point harness there is only one safe way to do it: Slotted seat, like a Recaro SRD, that will still fold forward, allowing you to put your helmet and track stuff behind the seats, Bolt-in Roll Bar, such as the fine bar from DAS-Sport Systems, and a good Five-point system such as the Schroth belts (sold by Steve Weiner at Rennsport) with the mounting points securely bolted through the floor of the car.

All up you are looking at about $2500 to do it right, I would think.

Good luck!

HarryD · 08:05 AM

Nostatic,

There are many issues to consider when using something other than the stock 3 point harness.

1-All harness systems need to be anchored properly;

2-The belts need to be routed in a safe manner. In the case of the shoulder harnesses, the straps need to be approximately parrallel to the floor wehre they pass over your shoulders to prevent compressing your spine during an accident. This leads to the requirement of a harness bar for 4/5/6 point harnesses. Three point belts address this issue by ensuring that the high attachment point for the shoulder strap is at or above your shoulder;

3-5 and 6 point harnesses prevent you from submarining under the lap belt and injuring your internal organs. Three point belts avoid this issue since your body will twist to keep you from sliding. Stroth's ASM technology claims to do the same thing for their 4 point belts by having one shoulder belt lengthen on impact forcing your body to twist and lock into position (their claim not mine);

4-4 point and higher harneeses hold you very firmly into the seat, and in an upright position. In the event of a rollover where the roof collapases, it is possible that your head can become the high point (ouch!);

5-In a 4+ pont harness it is very hard to reach the radio.

If you do a search here and at rennlist, you will find many posts on this subject. Wil Ferch has some very good points. I would also consult with one of the shops that do race prep to get a feel for the issues. Steve Weiner has been very helpful for me.

I use a Stroth 4 point harness for Autocross. I would not use it for the street as it is too restrictive and would be very hesitant to use it for DE due to the lack of a roll bar in my car. The Stroth Harness peacefully coexists with my three point belts and to use it I need to install my harness bar which prevents my children from riding in the rear seats.

Dantilla · 08-12-2003, 08:17 AM

Both of my Porsches have five-point harnesses. I tossed out the original three point belts. I drive them both on the street.

Not being able to reach the radio is no problem- I tossed that, too.

old_skul · 08-12-2003, 08:17 AM

I have 5-points in my Targa, with stock seats. The fit's a bit weird because of the seats but it's a world better than 3-points. I kept my 3-points in for daily driving.

Myself and a friend fabricated a harness bar from chromoly tubing and some stout plate. The harness bar bolts in concurrently with the 3-point shoulder point mount. The harnesses themselves go to the rear seatbelt bolts. I removed the rear seats and belts.

The bar can be removed from the car in 5 minutes if I really want to, but I leave it in because it looks cool and provides a tad more stiffness to the car. I also purchased regular-length G-Force 3" belts - which barely reached. I recommend the longer ones.

jyl · jyl's Garage

You may not volitionally duck out of the way, but as the roof crushes down the back of your seat, can your body fold with it in your factory 3-points, or will you be held upright by your racing harness?

Dantilla · 08-12-2003, 08:43 AM

Anything is possible.

What percentage of accidents in Porsches are a roll-over? I am convinced that I am safer in a carbon fiber race seat and five point harness than the stock set-up for over 99% of possible scenarios.

If that's too dangerous, I'm just staying in bed tomorrow.

304065 · 08-12-2003, 09:28 AM

Quote:

You may not volitionally duck out of the way, but as the roof crushes down the back of your seat, can your body fold with it in your factory 3-points, or will you be held upright by your racing harness?

When I used to use a 3-point only for DE, the procedure was:

1. Set seat in driving position.
2. Lift seat adjuster and slide seat back 3 inches.
3. With thumb under shoulder harness, lock inertia reel.
4. With inertia reel locked, slide seat forward 3 inches until seatbelt cuts into chest painfully.

You are now ready to drive. I blew an engine once, and the 3-point was so tight in this configuration that I couldn't release the belt. Tried to slide out from under the belt and my helmet caught, finally had to inhale all the way to get enough slack to get loose and put out the fire in engine compartment. Made me a believer in camlock five-points that day.

Anyway, with the belt that tight and the roof coming down, again we are assuming a rollover with 30g+, I just don't think anybody would be better off in a 3-point harness-- you are either held vertically by the belt, or the seat back deforms and you get crushed to the level of the doors. Not much of a choice.

I'll take it one further. With a proper seat, five-point and roll bar setup, you can focus your concentration on keeping the car on line, not on bracing yourself against the dead pedal in a left-quad isometric. This SHOULD allow you to decrease the likelihood that you will roll in the first place. . . and what about the feeling of confidence that comes from a roll bar? Again, a healthy dose of fear is a good thing to have, but knowing that you will walk away from a rollover can allow you to relax and concentrate on driving. . .

Plus there is nothing like the sight of a black-enameled cross-tube behind your head . . . tends to strike fear into the hearts of mere mortals. . . .

YMMV

nostatic · nostatic's Garage

so can one of the rear seats be used with a bar installed?

304065 · 08-12-2003, 10:36 AM

Quote:

so can one of the rear seats be used with a bar installed?

Roll bar?

Not unless the rider is a world-class Yogi with a death wish. In a collision the rider could impact the bar, and the rear seat lap belt is no help in that situation. If s(he) could even fit back there in the first place.

HarryD · 08-12-2003, 11:29 AM

Quote:

Originally posted by nostatic
so can one of the rear seats be used with a bar installed?

No, the bar extends across the entire width of the car. My Stable Energies bar is attached to the upper mount points of the shoulder staps. It's design also allows my 3 point belts to peacefully coexist with the harness so I can drive on the highway to the event and operate the radio.

Even my kids (8 and 10) hit their (cute

) little heads on the bar.

The good news is that it takes me only about 5-10 minutes to install or remove the bar.

dotorg · 08-12-2003, 11:35 AM

I wonder how bad it would be to run harnesses for a short time without a bar on a seat that has harness guides like an SRD... Those of us with lowly '68 cars don't have the mounting points these new-fangled harness bars and mail-order roll bars bolt onto. I have to get something custom made...

HarryD · 08-12-2003, 11:43 AM

Quote:

Originally posted by dotorg
I wonder how bad it would be to run harnesses for a short time without a bar on a seat that has harness guides like an SRD... Those of us with lowly '68 cars don't have the mounting points these new-fangled harness bars and mail-order roll bars bolt onto. I have to get something custom made...

Are you sure there is not the upper mounting point already drilled and tapped on your B pillar? I thought most p-cars were designed for 3 point restraints even if they were not installed.