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Discussion Starter #1
I'm working on bringing my '68 Mustang coupe back from the dead and I'm about to start working on the interior. It's going to be a street car, so will probably only see a track maybe once or twice a year. I'd like to get away from the lap belts and get something a little more secure. What I had in mind was a roll bar and harness similar to the '67-'68 Shelbys. That way I'd be able to keep the rear seats functional so I can take my kid along with me and the wife. All the Internet experts say this is a bad design because the rear passenger could crush their head on the roll bar in an accident, or the harness is mounted to high and you'll crush your spine, and don't run a 4 point harness because in an accident you'll slide down (submarine) and crush your torso, etc.

So what's the real deal? Am I making the restraints less safe than the car originally came with, with just lap belts or am I making it slightly safer but not nearly as safe as what the sanctioning race bodies would like to see?

Here's a pic of what the Shelby bar and harness look like for those that don't know.
 

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If you are thinking about doing a roll cage, take a drive over the Maier Racing, on Meekland, in Hayward. Mike is a wealth of info and a great guy.
Stan
 

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I'm working on bringing my '68 Mustang coupe back from the dead and I'm about to start working on the interior. It's going to be a street car, so will probably only see a track maybe once or twice a year. I'd like to get away from the lap belts and get something a little more secure. What I had in mind was a roll bar and harness similar to the '67-'68 Shelbys. That way I'd be able to keep the rear seats functional so I can take my kid along with me and the wife. All the Internet experts say this is a bad design because the rear passenger could crush their head on the roll bar in an accident, or the harness is mounted to high and you'll crush your spine, and don't run a 4 point harness because in an accident you'll slide down (submarine) and crush your torso, etc.

So what's the real deal? Am I making the restraints less safe than the car originally came with, with just lap belts or am I making it slightly safer but not nearly as safe as what the sanctioning race bodies would like to see?

Here's a pic of what the Shelby bar and harness look like for those that don't know.
The real deal is how safe do you want to be and your kids? My opinion is that the Shelby bar and belt and stock seats are a death trap on the track and I would NEVER sit anyone 2 feet away from a 1.75" .120 thick tube of unprotected steel unless they were fully restrained and wearing a helmet.

Personally I won't take my kids in the back without a roll bar and I won't go on the track without a roll bar and 5pt harness. I built a fully removable roll bar:



 

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Discussion Starter #4 (Edited)
The real deal is how safe do you want to be and your kids? My opinion is that the Shelby bar and belt and stock seats are a death trap on the track and I would NEVER sit anyone 2 feet away from a 1.75" .120 thick tube of unprotected steel unless they were fully restrained and wearing a helmet.

Personally I won't take my kids in the back without a roll bar and I won't go on the track without a roll bar and 5pt harness. I built a fully removable roll bar:
Why is the Shelby setup a death trap? Can you please elaborate?

As for someone being in the back seat without a helmet, what would be the difference of smashing into the roll bar without a helmet and smashing into the roof without a helmet? Are you saying that hitting your head on the rollbar is a greater risk than riding around in a car with only lap belts? The NTSB has known for years that lap belts alone can cause severe spinal and abdominal injuries. Here's a study they released in 1986 regarding lap belt only injuries.
http://mvhap.org/mvhappdfs/laprestraint.ntsb.study.26crashes.7.28.86.pdf

Here's an interesting excerpt from that study.

Among the 50 persons using a lap-only belt, the
Board determined that at least 32 of them would have fared substantially better if they
had been wearing a lap/shoulder belt. In many cases, the lap belts induced severe to
fatal injuries that probably would not have occurred if the lap belts had not been worn.
The occurrence of lap belt induced severe to fatal injuries was not limited to severe
crashes: 14 lap belted occupants sustained belt induced injuries of AIS 3 or greater
severity (including 6 fataliy injured) in crashes of Delta V 28 mph or lower.
 

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Why is the Shelby setup a death trap? Can you please elaborate?
The shoulder mounting point is too high and there is no headrest and too much 'give' in that seat.

As for someone being in the back seat without a helmet, what would be the difference of smashing into the roll bar without a helmet and smashing into the roof without a helmet? Are you saying that hitting your head on the rollbar is a greater risk than riding around in a car with only lap belts? The NTSB has known for years that lap belts alone can cause severe spinal and abdominal injuries. Here's a study they released in 1986 regarding lap belt only injuries.
http://mvhap.org/mvhappdfs/laprestraint.ntsb.study.26crashes.7.28.86.pdf

Here's an interesting excerpt from that study.
Lap belts are better than nothing but my kids will ride around in the back with 3pt belts.
 

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Discussion Starter #6
The shoulder mounting point is too high and there is no headrest and too much 'give' in that seat.
Sorry, should have mentioned, the front seats are most likely going to be Corbeau's with shoulder belt slots.


Lap belts are better than nothing but my kids will ride around in the back with 3pt belts.
Did you read the study? Apparently lap belts are not better than nothing.
 

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Discussion Starter #7
If you are thinking about doing a roll cage, take a drive over the Maier Racing, on Meekland, in Hayward. Mike is a wealth of info and a great guy.
Stan
Yeah, I've been down there before. Cool shop in the middle of the ghetto. :D Gotta love Hayward.
 

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Sorry, should have mentioned, the front seats are most likely going to be Corbeau's with shoulder belt slots.




Did you read the study? Apparently lap belts are not better than nothing.
Read this - http://www.gforce.com/pdf/Harness_Install_Info.pdf. Mounting the shoulder belt on the roof and using the seat belt slots to route the belt down to your shoulders is not correct.

I didn't read the study because I don't use lap belts.
 

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Discussion Starter #9
Read this - http://www.gforce.com/pdf/Harness_Install_Info.pdf. Mounting the shoulder belt on the roof and using the seat belt slots to route the belt down to your shoulders is not correct.

I didn't read the study because I don't use lap belts.
I wholeheartedly agree that in a race car application that is 100% the correct way to install a harness. I've read several instructions on how to do it. However, I am not building a race car, I'm building a street car. What I want to accomplish is making the car more safe than it came from the factory in 1968. I realize it's not going to be SFI 16.1 safe. Currently the car only has lap belts. I am uncomfortable with this arrangement.

Let me rephrase my question regarding the front seats and belts.

Is the risk of being severely injured by wearing a 4 point harness with the mounting point above the shoulder line greater or less than wearing lap belts alone? The NTSB concludes that wearing lap belts only presents a high risk of severe injury or death in frontal impacts at speeds as low as 28mph.
 

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I am not building a race car, I'm building a street car.
But you are going on the racetrack right? Your car or body won't know if you are racing or not if you hit the wall.

I'm in the same boat as you. I only have one car and I like to drive on the street but I'm also addicted to the racetrack. I started out on track with stock seats and terribly mounted 4 pt belts, way back then I didn't know any better. Now I do and you should read, learn and listen to advice on how best you want to setup your car. You can set it up how you like, its your car but safer is better and if you are already in the build stage, buy that Shelby bar and have someone put a harness bar at the correct height as well as rear down legs. Have them build it to the current SCCA rules. Use your Corbeau seats and figure out how to mount a sub-belt.

I'm not trying to be a dick, I just want you and the people around you to be as safe as possible.
 

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Discussion Starter #13
I'm not trying to be a dick, I just want you and the people around you to be as safe as possible.
Understood. So if the Shelby setup is unsafe (I'm fully willing to accept that) and I'm unwilling to install a rollbar with a cross bar to properly mount a 4 point harness, then what are my options to providing a safer restraint system than the factory lap belts?
 

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I haven't measured things out but I always wondered in the absence of an interior to screw up, could you sneak in a roll bar somehow tucked up against the sheet metal and hide most of it so it does not show or "impact" little heads in the back? Then provide a good mounting point for a 3 point system? I was looking at a friend's 68 frame up sans interior and it seemed (without really diving into it) that there was room. Bracing back might be a challenge but...

I wish I had never clicked on this link - I was much happier in my ignorance!

M
 

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Understood. So if the Shelby setup is unsafe (I'm fully willing to accept that) and I'm unwilling to install a rollbar with a cross bar to properly mount a 4 point harness, then what are my options to providing a safer restraint system than the factory lap belts?
Buy a modern Mustang?

I don't know. I've been slowly developing my car for 11 years to do dual duty. The best I could come up with is a removable roll bar. I can have it out and the rear seat installed in an hour or so.
 

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Discussion Starter #16
Buy a modern Mustang?

I don't know. I've been slowly developing my car for 11 years to do dual duty. The best I could come up with is a removable roll bar. I can have it out and the rear seat installed in an hour or so.
So then when you have the roll bar out of the car, what do you use for belts?
 

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A roll bar with Shelby type belts is better than just lap belts. It will definitely help in a side collision. You can talk all day about "spine compression" but eating the steering wheel wearing just lap belts is a much greater concern IMO.
 

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You need a Shelby style rollbar with a bolt in cross bar to attach your 5 point harnesses. The Shelby style belts at the top of the roll bar are too high, and illegal at most tracks.
 

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Read the full report rather than grabbing on sentence that supports your claim. About 75% of the injuries were to children and people incorrectly wearing the belt. Belts were designed using a 150lb crash dummy, properly and snugly belted. By that rational ABS doesn't work on doors(cause it wasn't designed for doors!) and ABS doesnt work if the brakes are not applied(Duh!).
Regardless, you want the best system available for your application. 3 point, self tightening, inertial reel, 1 continuous belt for street is a minimum. 5 point is the minimum for track.
 

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Discussion Starter #20 (Edited)
Read the full report rather than grabbing on sentence that supports your claim. About 75% of the injuries were to children and people incorrectly wearing the belt. Belts were designed using a 150lb crash dummy, properly and snugly belted.
I did read the whole thing, and I don't see where your claims are supported in it. I don't see where it says 75% of the injuries were to children and people incorrectly wearing the belts.

Even correctly² worn lap belts induced severe injury: 24 occupants who received AIS 3 or greater injuries from the belt itself are believed to have been wearing it correctly.
2: There is no offiicially agreed-upon definition of "correct" lap belt use, but the Safety Board used the term to mean snugly crossing the lower abdomen between the pubis and the umbilicus, with the belt low on the hips below the crest of the ilium, This appears to be the generally accepted meaning.
The ages of lap belt injured persons ranged from 4 to 82 years (more than half were younger than 15 years' however) and included both males and females.
 
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