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My understanding is that if you take your shoulder straps and run them down to the seat floor (as many people do), that if you wind up in an accident it will break your collarbones or worse, your spine.
Is this true? What causes it? What makes the harness bar safer, is it that the mount is behind rather than below the driver?
My understanding is that if you take your shoulder straps and run them down to the seat floor (as many people do), that if you wind up in an accident it will break your collarbones or worse, your spine.
Is this true? What causes it? What makes the harness bar safer, is it that the mount is behind rather than below the driver?
Don't have one, just curious!
Schroth has the best information on this but to paraphrase:
Its because in the event of certain types of vehicle motion (especially a roll over) the harness holds you firmly at your waist and if its not properly aligned all the stress goes to your lower spine.
A three point is vastly superior for the road because in the event of a roll over as it transitions energy across your body and lap but will allow you to drop through the top reducing stress on your lower spine.
The new Schroth harness actually have a tear away that allow them to elongate on one side similar to the three point harness. So you can run some of the new Scrhoth harnesses on the street as they act like a three point in the event of a collision.
I tracked my C6 coupe at speeds up to 170. I had to install a harness bar and 6 point harnesses to be able to pass tech inspection. My understanding is that having a harness bar and aftermarket harnesses hold you in place, but do not push you down as a factory shoulder harness does. That can, in certain high speed violent crashes, protect the spine from compression fractures.
I can tell you that when I tightened my 6 point harness I had almost no movement of my body in the seat, which is a good thing for high speed racing. I can also attest that the shoulder straps pulled me back into the seat instead of pushing me down into the seat.
All that said, I don't track my C7 because it's a vert, and I don't worry about the shoulder strap pushing me down into the seat in a violent crash as I figure there are much more important things to worry about, like safe driving habits and watching the idiots around me to avoid a crash. The forces in a typical legal speed crash are nothing like the forces in a 150+ mph racing crash.
Thanks! I'm still not really clear on the mechanics of what happens to the body, but it's clearly a "bad idea".
Its called submarining here is a diagram from Schroth
"The risk to submarine (sliding underneath the lap belt), a well known phenomenon during frontal impacts, is significantly reduced by the asm® safety system. The energy converter is located in one of the shoulder belts. Severe injuries or death are possible using 4-point harnesses without the SCHROTH asm® safety system or an anti-sub strap. SCHROTH harnesses designed for use on public roads (FE push button models) or those likely to be used as 4-points come with the asm® safety system. The performance of the SCHROTH asm® safety system has also been positively tested in conjunction with airbags."
The harness is awesome at a track because it pins you to the seat and with lots of corners you are held flat to the seat, the downside to daily driving is that you can't lean forward for doing shoulder checks or looking over your shoulder while backing up.
Its called submarining here is a diagram from Schroth
"The risk to submarine (sliding underneath the lap belt), a well known phenomenon during frontal impacts, is significantly reduced by the asm® safety system. The energy converter is located in one of the shoulder belts. Severe injuries or death are possible using 4-point harnesses without the SCHROTH asm® safety system or an anti-sub strap. SCHROTH harnesses designed for use on public roads (FE push button models) or those likely to be used as 4-points come with the asm® safety system. The performance of the SCHROTH asm® safety system has also been positively tested in conjunction with airbags."
The harness is awesome at a track because it pins you to the seat and with lots of corners you are held flat to the seat, the downside to daily driving is that you can't lean forward for doing shoulder checks or looking over your shoulder while backing up.
Do you not feel pinned enough by locking the 3 point belt? I can't move an inch forward or down when I lock it.
Do you not feel pinned enough by locking the 3 point belt? I can't move an inch forward or down when I lock it.
Compared to an actual harness? A three point is not even a comparison to a 4 point or etc in terms of how firmly it hold you to a seat, you need to experience it to understand, if you are doing any lapping you might not realize how much stress you are putting into the leg on the dead pedal. With the 4 point you don't even wiggle. As well its important to note if you are racing or lapping IMHO you should have a HANS device, which are designed to be used with harness systems. The average human head is 11 lbs then toss a helmet on there, even if its only an off track excursion you will end up with a sore neck, a HANS device transfers the stress to your core and that is supported with a harness. The harness bar is needed for the proper angle on most cars to prevent spinal damage in collisions or rolls.
Anyway take it for what its worth, I was just trying to address the OP's questions. I have not installed a harness in my vette yet, but I did several lapping days last year and recently acquired a Schroth belt setup and harness bar for the car. I had one in my previous Audi and it makes a world of difference when you are pushing the car to the limit at a track.
Compared to an actual harness? A three point is not even a comparison to a 4 point or etc in terms of how firmly it hold you to a seat, you need to experience it to understand, if you are doing any lapping you might not realize how much stress you are putting into the leg on the dead pedal. With the 4 point you don't even wiggle. As well its important to note if you are racing or lapping IMHO you should have a HANS device, which are designed to be used with harness systems. The average human head is 11 lbs then toss a helmet on there, even if its only an off track excursion you will end up with a sore neck, a HANS device transfers the stress to your core and that is supported with a harness. The harness bar is needed for the proper angle on most cars to prevent spinal damage in collisions or rolls.
Anyway take it for what its worth, I was just trying to address the OP's questions. I have not installed a harness in my vette yet, but I did several lapping days last year and recently acquired a Schroth belt setup and harness bar for the car. I had one in my previous Audi and it makes a world of difference when you are pushing the car to the limit at a track.
Did you use the belt lock method on the corvette? Im serious, i don't move at all between that and the bolsters on the seat. Maybe my body fills perfectly.
Autocrossing in my old mustang i remember my knees banging on the door.
My understanding is that if you take your shoulder straps and run them down to the seat floor (as many people do), that if you wind up in an accident it will break your collarbones or worse, your spine.
Is this true? What causes it? What makes the harness bar safer, is it that the mount is behind rather than below the driver?
Don't have one, just curious!
My god, don’t run shoulder straps to the floor! A harness is designed to keep you from moving. It should not be used on the street! The biggest issues with a harness is neck injury. If wearing a harness one really needs a helmet with HANS device to stop your neck from braking. The harness will hold your body in place and your head is not so lucky. Hence the reason a harness should not be used on the street without a helmet/HANS set up. The submarine effect happens from incorrectly installed/measured seat to harness relationship.
Another issues commonly debated is roll over protection. Many think a cage is required to safely run a harness set up in the event of a roll over. I’m in the camp of, if GM will put there employee/egineer in a ZR1 with Race seat, harness, and HANS, then I’m good to go.
My god, don’t run shoulder straps to the floor! A harness is designed to keep you from moving. It should not be used on the street! The biggest issues with a harness is neck injury. If wearing a harness one really needs a helmet with HANS device to stop your neck from braking. The harness will hold your body in place and your head is not so lucky. Hence the reason a harness should not be used on the street without a helmet/HANS set up. The submarine effect happens from incorrectly installed/measured seat to harness relationship.
Another issues commonly debated is roll over protection. Many think a cage is required to safely run a harness set up in the event of a roll over. I’m in the camp of, if GM will put there employee/egineer in a ZR1 with Race seat, harness, and HANS, then I’m good to go.
I tracked my C6 coupe at speeds up to 170. I had to install a harness bar and 6 point harnesses to be able to pass tech inspection. My understanding is that having a harness bar and aftermarket harnesses hold you in place, but do not push you down as a factory shoulder harness does. That can, in certain high speed violent crashes, protect the spine from compression fractures.
I can tell you that when I tightened my 6 point harness I had almost no movement of my body in the seat, which is a good thing for high speed racing. I can also attest that the shoulder straps pulled me back into the seat instead of pushing me down into the seat.
All that said, I don't track my C7 because it's a vert, and I don't worry about the shoulder strap pushing me down into the seat in a violent crash as I figure there are much more important things to worry about, like safe driving habits and watching the idiots around me to avoid a crash. The forces in a typical legal speed crash are nothing like the forces in a 150+ mph racing crash.
eh... keep in mind on the street you could be going 70 and get hit by an idiot going the opposite way at 70 on a country road. that's a 140 mph crash.
Last edited by BrunoTheMellow; 05-24-2018 at 01:40 PM.
Did you use the belt lock method on the corvette? Im serious, i don't move at all between that and the bolsters on the seat. Maybe my body fills perfectly.
Autocrossing in my old mustang i remember my knees banging on the door.
I have tried the 3 point belt lock, it is not nearly effective enough on a track for lapping or time attack. My local track has a lot of elevation change and fast corners so a three point factory belt is not ideal.
My last TA/lapping car was an audi and I had run harness, bar, seats and left the OEM three point in for street use.
I agree that the three point should be used for the street but the harness really shines at a track.
The problem with running the shoulder harnesses down to the floor is spinal compression. In an incident the harnesses stretch as the body is thrown forward. The direction the belts take as they come off your shoulders can increase the compression force on the spine as the belts stretch. All of the harness makers pretty much say the maximum down angle from the shoulders to the belt mounting point shouldn't be more than 20 degrees.
A 4 or 6 point harness will hold you in place better than a 3 point harness but you won't be able to tell that by just driving around a track. I can tightly fasten any 3 point system that has a cinch feature like the Corvette has. I can get the 3 point system in any Corvette made since the 1984 model year with a power seat installed so tight across the chest the occupant will have trouble breathing and the lap belt will feel like it is cutting them in half. The three point system reduces the chance of submarining by letting the upper body pivot around the shoulder belt. This transfers weight forward and upward so the lap belt holds the lap in place. Most newer cars also have knee guards that keep the occupant's legs from moving very far forward.
If you remember the Spring Mountain instruction on how to adjust your seat you will remember them talking about having your knees close to the lower dash panel with the front of the seat bottom tilted upward so it cupped your butt to reduce the chance of sliding forward. Then you fasten the belt so the lap belt is across your pelvis not your belly. People with overhanging beer bellies need to lift the overhang and place the belt under it.
eh... keep in mind on the street you could be going 70 and get hit by an idiot going the opposite way at 70 on a country road. that's a 140 mph crash.
Well, yeah, that's true, but if we're talking about a head-on crash at 140, or the equivalent, you're in a world of hurt in anything but a fully caged race car, with the driver in a 4 or 6 point harness, and full helmet and HANS. That kind of crash in any street car will result in serious injury, or death, regardless of what kind of harness you're in.
Well, yeah, that's true, but if we're talking about a head-on crash at 140, or the equivalent, you're in a world of hurt in anything but a fully caged race car, with the driver in a 4 or 6 point harness, and full helmet and HANS. That kind of crash in any street car will result in serious injury, or death, regardless of what kind of harness you're in.
Agreed, as thats a lot of energy! Even caged with all safety gear, your personal condition can determine if you die from your internal organs decelerating at a silly G level.
Agreed, as thats a lot of energy! Even caged with all safety gear, your personal condition can determine if you die from your internal organs decelerating at a silly G level.
Yup. Trying to "what if" a 140 mph head-on crash is silly. The most likely result is death, no matter what you're wearing or driving.
Yup. Trying to "what if" a 140 mph head-on crash is silly. The most likely result is death, no matter what you're wearing or driving.
You guys need to revisit your physics, if two cars with the same mass collide at 70mph it is not equal to 140mph, it’s equal to a Car hitting a wall at 70mph.
You guys need to revisit your physics, if two cars with the same mass collide at 70mph it is not equal to 140mph, it’s equal to a Car hitting a wall at 70mph.
"for every force there is an equal and opposite force"
If two cars with similar mass and speed collide at 70mph it is just a 70mph crash it is not the same as a 140mph crash.
Kinetic energy is based on the square of the velocity, so a car moving at twice the speed would have 4 times the velocity. Momentum is the mass x velocity so if both cars have similar mass and velocity... it is a 70 mph crash it is not the same as a car moving twice the speed @140mph.
05-24-2018, 11:00 AM
Harness Bar Question (Why its needed)
