Rollbar fit under hardtop?

DELETED · Post by **DELETED** » Wed Apr 20, 2005 6:48 pm

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SLOroadster · Post by **SLOroadster** » Wed Apr 20, 2005 9:50 pm

Conner,
To answer your question, no it doesn't offer any protection, however it does work as my bike rack. How else can you put 2 bicycles on a car with no top, or bumpers? I'm hoping to find a tall windshield rollbar by Shasta.

Will

Redtail · Post by **Redtail** » Thu Apr 21, 2005 11:53 am

Cool Alvin, that's basically what I'm wanting to do for my brake light. just without the electrical tape. hopefully.

As for protection of the roll bar, I know it's been covered a thousand times, but I have to think the bar will do something for you in a roll over. It might not be much, but even if it just brakes off it still takes some force to do that. IMO if you put reinforcement plates under the parcel shelf mounting points, and fabricate some kind of brace welded to the frame for the main hoop it would offer a decent amount of protection. or at least a little more than no bar at all.

just my non-scientific, non-tested hopefull opinion though...i could be wrong.

DELETED · Post by **DELETED** » Thu Apr 21, 2005 12:20 pm

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Redtail · Post by **Redtail** » Thu Apr 21, 2005 3:45 pm

Have any extras of those backing plates Alvin?

DELETED · Post by **DELETED** » Thu Apr 21, 2005 4:12 pm

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nomadtrash · Post by **nomadtrash** » Thu Apr 21, 2005 8:50 pm

I've posted on this list and others lots of times about rollbars. If it will fit under the top then it will give you NO protection at all. When you roll the car over it will hit the ground in two points. Point A is the rollbar and Point B is the highest place at the front. This happens to be the top of the hood. The top of the hood, headlight buckets, radiator and anything else up there will not provide any structural support. The motor will be what supports the weight of the car when it is upside down. If your noggin contacts a line drawn from the top of the rollbar to the valve cover then your head becomes Point B. I don't know anyone that is thick headed enough to support the weight of a roadster with their noggin.

Secondly, the floorpan of the roadster is not very strong. You will notice that the seats are bolted to a large thick steel brace. If you attach a rollbar only to the floorpan then when you support the entire weight of the car on it then it will punch right through. Most probably the seams will split along the rockers and the package shelf.

Thirdly, a rollbar requires a rear brace to keep it from folding up while skidding along. The rear brace can see much more load than the main hoop because of the leverage against it. It will also punch right through the package tray and rip the seams out.

Fourthly, rollover forces tend to rip the bar out of the car when you are skidding along. There has to be a backing plate at least as large as the mounting plate on top. In the roadster the backing plate will pull right through and split the seams.

The only way to build a rollbar that can give you any saftey is to do these things:
1. The main hoop must be high enough that your head isn't in line with the rollbar and the structural portion of the front of the car.
2. The main hoop should be of a diamter and wall thickness to support the weight of the car. (2" dia. x .120" thick)
3. Two rear braces should be attached in the top third of the height of the main hoop and should be at an angle of no steeper than 30 degrees.
4. The mounting pads of the main hoop and rear braces should be welded or very securely bolted to the frame.
5. Driver restraints should be used to ensure that no portion of your body gets outside the protective envelope. IE head out the window.

With all this being said, it is important to note that Datsun Roadsters are not Volvos. They were never designed, constructed, or intended to be safe in a rollover. The cars are inherently safe not because of the design of the cars but because of the domographic that ownes them.

If these cars get popular with the soccer moms then I'll start marketing a rollcage kit immediately.

I've come to the conclusion that if I flip I will probably get squished or my brain will be "shake and bake". My racecar has the minimal rollbar that just barely meets SCCA rules. It would not protect me in a rollover.

In conclusion I say put in the "street" rollbar if you want to look cool. Realize that it does nothing but look cool. Understand that you wouldn't have purchased this car if any form of crash saftey was a priority.

Sorry for the rant,

DatsunBucky · Post by **DatsunBucky** » Thu Apr 21, 2005 9:38 pm

nomadtrash wrote:The cars are inherently safe not because of the design of the cars but because of the domographic that ownes them.

I mostly agree with what nomadtrash wrote.

To paraphrase wise old Mr. Miyagi, "The best way to survive an accident is to not be there when it happens."

<lecture mode>Many of the things I learned 35 years ago autocrossing (then called slaloming) are still with me today, and I have not driven competitively since 1978. They became reactions, rather than thoughts. Too many people today, when confronted with a situation requiring immediate analyzation and instant action, do nothing more than slam on the brakes and rely on the safety features built into the car by someone else to help them survive.

I sincerely believe that I have not only survived, but avoided many situations by being ultra-defensive and working the steering wheel rather than the brakes. So what if we don't have ABS? Don't need it. That the car responds instantly instead of heeling over on those nice soft springs before responding is at least as important as an airbag in front of the passenger. Not to mention how many small children bore the brunt of an airbag deploying before the Ralph Naders who call the shots came up with the graduated deployment method we see today. </lecture mode>

DELETED · Post by **DELETED** » Thu Apr 21, 2005 9:41 pm

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nomadtrash · Post by **nomadtrash** » Thu Apr 21, 2005 9:52 pm

Now someone should bring up seat belts so that I can go on another 30 minute rant. Ever heard of the 90th percentile male? It isn't me for sure.

DELETED · Post by **DELETED** » Thu Apr 21, 2005 10:04 pm

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nomadtrash · Post by **nomadtrash** » Thu Apr 21, 2005 10:15 pm

I feel bad for jacking this thread. I'll be brief.

Factory seatbelts are tested with the 90th percentile male in mind. I think he is 5'9" and weighs 150 pounds. If you are bigger like me or "gorrilla boy" Eric Frisbee then they will snap. If you are a tiny little "monkey boy" then other bad things can happen.

5 or 6 point racing harnesses are the only way to go.

DELETED · Post by **DELETED** » Thu Apr 21, 2005 10:19 pm

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nomadtrash · Post by **nomadtrash** » Thu Apr 21, 2005 10:45 pm

I wasn't talking about roadsters. I was talking about all new cars. I wouldn't trust the roadster belts to hold anybody. I use a 2 point OEM belt in my street car. It is habit and I feel uncomfortable driving without a belt on. It probably wouldn't do much but rupture my intestines and break my spine in an accident. Luckily I would probably do the Dale Earnhart on the steering wheel anyway.

In the race car I use a 5 point.

If the banana fits...

SLOroadster · Post by **SLOroadster** » Fri Apr 22, 2005 12:57 am

I've gotten so used to my 5 pts that regular belts make me feel unsafe. The ricer guys give me strange looks when they see me straped in with the shoulder harnesses just driving around town. I almost swapped a set into the Miata I was driving while my car was dead. I seem to wierd out my passengers however.

Will