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Not compensating at all
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I see it like this... As long as your seat is bolted down right, then you won't have any problems if an accident occurs.
I think what those "few" people were concerned about is if an accident happens and the car say rips apart, that could be a huge problem.
I would say it's probably 95%+ safe to run the harness without a cage. Hope that helps some.
 

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Think about your pivot points of you harness when you're in a head on collision. Your shoulders pull the harness and the seat forward with tremendous force and could fold the seat right over into the steering wheel like you have no harness at all. That's why folks drape the harness, between where it leaves your shoulders and bolts to the floor, over a cross piece on a roll cage. All the force is on the cage.

Eric
 

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say your in a roll over.........have the harnesses on

the harnesses dont allow you to slide down in your seat...

your head is the only thing keeping the roof from coming in




thats what adrocktt told me that made me pick up the phone and order a roll cage to be installed
 

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Inline for the win
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With race harnesses mounted to the back of the seat brackets w/o going over the crossbar of a cage creates the pivot point to be now occuring at your shoulders and all the way down the back of the seat.

It will end up breaking the seat or your ribcage from the seat collasping when you are involved in an accident.

The cross bar in a roll cage puts that point of stress on the crossbar. IMO, its easier to collaspe a race seat instead .065 wall 4130 chromoly tubing which has a lower deformation characteristics and higher stress capabilities than and race seat or factory seat.


Just from a Industrial/Mechanical engineer's view.
:D
 

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The reason for the statement is that a harness will hold you upright in a rollover increasing your chance for serious head injuries. In any other type of colision they are vastly superior. Carl Byck
 

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TRNSFST
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Yup. Don't wear 4 point, or 5 or 6 for that matter, without a cage. It's just not a good idea.

You can't go anywhere in those things, and in a rollover, all you could do is hope the roof doesn't crush...don't do it without a bar or cage.

billy
 

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Bleh, if I wrecked my supra, I think I might as well die in the crash!
Seriously, would you suggest a full roll cage, or just the rear portion? I dont want the front one to get in the way and I lose some functionality/comfort of the vehicle. I dont really run my vehicle (yet) and taking this into consideration, what would you do?
Sparco makes a nice looking harness bar (No protection if you roll)
Rear roll cage (fabricated or pre-made) offers some protection if you roll, but I hear it helps support the vehicle inside.
Full roll cage w/ front supports, offers the best protection but you lose some functionality and comfort.
I guess it totally depends on what you plan on using the car for...street or track, and how often you race on either.
 

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TRNSFST
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If you just get the rear half cage, then you would be fine running a 4 point harness.

I would go with the rear half cage if I were you, seeing as you don't want to lose comfort etc..
 

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Thats what I was thinking...thanks for confirming. I can always add the front portion at a later date as well...so no huge decision has to be made if I got with rear only.
 

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TRNSFST
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you're off to a better start than most people by getting the cage.

Just remember, that bar's gotta be above your head. Also, make sure you get a harness bar with the cage. It will be horizontal, and right below the top bar that's behind your head.
 

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Not hijacking thread,... but Yikes!!!! ; rjhoskins, nice car! It's too d#%mn clean!(old school)
If I may ask, who did your rollbar? That's one of the cleanest installs i've ever seen on a Supra. Is it a kit?
Anyone know of a shop in TX. that can do work like that??
Thanx....
Will
 

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supraman111 said:
say your in a roll over.........have the harnesses on

the harnesses dont allow you to slide down in your seat...

your head is the only thing keeping the roof from coming in




thats what adrocktt told me that made me pick up the phone and order a roll cage to be installed
:agreed: Roll that car with harnesses no cage and you aren't going to have an open casket funeral. Hit something fast enough and you'll break the seat too. Both are a risk. Get a harness bar and rollover protection and then use harnesses as ADDITIONAL safety versus a death trap. The ONLY use I've ever seen for harnesses with no cage is with the auto cross crew going like 40-60 mph TOPS in a parking lot who need to be held in place left and right wise as they turn hard. If this is you, just wear them at the event.

Adam
 
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I believe that you just need to mount the harnesses at a 45 degree angle. I think it is safe to mount them in the rear seat if you dont need a roll cage. It is better to mount them to the cage though.
 

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Undefinable
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I hadn't heard about the rollover dangers of a harness w/o a cage, but it makes sense. What I have seen people do that is horribly wrong is bolting the harness to the seat. I don't care how strong your seat to car mounting is... don't try it. Bolt the harness to the cage if you have one, or the actual car (floor, pillar, etc.) if you don't.

I sat in on a fatality briefing about a Marine in CA who killed the USAF NCO who was riding with him. Someone pulled out in front of him on the hwy and caused an accident. Since the Marine bolted the harness to the seat... when the seat broke loose, the NCO was killed bcz she and the seat collided with the dash and windshield. She was no safer in that instance that if she had been unbelted.
 

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I bought a g-force 5 point harness thinking I would bolt the shoulder harnesses down back in the rear seat "bulkhead" area. I don't have a rollbar. I had heard from a friend that it was not recommended to have the shoulder belts anchor down so low due to risk of compression of the spine. I thought well it should be better than stock belts and if belts stretch about 20% or so in impact how could it compress the spine with the seat height anyhow.

Well, I went to the SCCA National Convention in Kansas City, Mo. in early February to do my duty as an RE and politic and schmooze. This year they had something new which was great. They had several safety symposiums. One of them on Saturday was a two hour seminar on racing harnesses, seats, and HANs devices. The speakers? Industry heavyweights, Arnie Kuhns, Pres. of SFI Foundation. Hubert Gamling, Safety consultant on loan from Mercedes to the FIA Foundation (he works with Prof. Sid Watkins). Dr. John Melvin, Pres. of Tandelta Corp. Carl Schroth, founder of Schroth Safety Products, and Dr. Bob Hubbard, inventor of the HANs device.

Well I got the answer I did not want to hear. Dr. John Melvin is like Mr. Crash Test Dummy. He has done tons of simulated crashes using various racing harnesses, racing seats, netting, HANs devices, etc. I looked at so many crash tests and real footage my neck hurt. I asked Dr. Melvin about anchoring the shoulder belts back and down to the back seat area. He told me not to do that in that it can create a risk of injury/compression to the spine. Carl Schroth said the shoulder belts should not drop down more than 20 degrees and no more than two inches below the shoulder. Of course I find Schroth's statment on that interesting in that he sells a four point "clubman" system to the public that uses the rear female seat belt end to clip into for its anchor and in my experience as an instructor in cars with belts of this type, the damn things ride up way too high at the lap belt (maybe spinal injury-displaced vetebrae/colostomy bag). Dr. Melvin said if I end up in a car with that set up try and use the regular restraint system too!

Also if you have belts that are pretty long it was recommended more than once that you cross them over each other going back to the anchor points. They showed pictures of both good and horrible seat belt set ups. Also if you do have a roll cage they said that the foam padding people typically used was worthless in impact. You are to use SFI-45.1 padding two inches thick. BSR Products sells it.

Oh yeah, Hutchins device does virtually nothing against forward head motion (potential nut cutter though). HANs offers 50% decrease if worn right. They have had some drivers experience 139gs and not even have a sore neck the next day. It would blow your mind to see just how far you head moves forward on impact with the best harness set up without the HANs. If my wife had watched the footage I watched, especially the real world crashes she probably would not let me on a track.

Barry H.
 
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