333pg333

Are they going to do anything in a rollover? I know this is open to many variables but assuming you've flipped and land on the roof I don't imagine the windscreen is going to stop you from getting severely injured or worse.
Opinions?

Porsche917K

Generally no. They are a good mounting point for harnesses but will not hold up very well in a serious crash. There are a few well built and strong bolt in options out there for some cars though. GMG makes a pretty nice one for the GT3.

333pg333

So really they're just a glorified harness bar? I suppose the likelihood of flipping is much more when racing vs time trials, but probably better to be sure than sorry.

Flying Finn

I disagree to some extent (BTW, I used to have a roll bar but now have a cage).

IMO in principle you can look at them like "roll bars" in an open wheel cars, they don't have windshield either. If you draw an imaginary line from the top of the roll bar to the top of the hood (or maybe fenders) of your car, that line is what is "between" you and asphalt when you're upside-down.

I'm not really any kind of safety expert, just an uneducated opinion.

M758

They are far better than nothing at all. In a flat crash (ie no roll) the can at as solid mounting for a harness. In a roll over they will protect the b-pillar from collapsing and since your head is near the b-piller they will help protect you. They are not as effective as full cage, but I think a excellent compromise for street driven cars as you get good benefits, but much less chance of head to bar contact on the street.

RedlineMan

Hey;

Let's break this down a bit into two main areas of incursion.

To the extent that the rear roof area stands to come DOWN, they are then useful, and obviously desireable. That extent is usually minimal in reality. The most vulnerable portion of any car roof - by far - is the distance between the cowl and the b-pillar, the longest unsupported length of metal in any car, even with a cage. Taking steps to buttress this area is ALWAYS a good idea. To wit;



Where they stand to do you the most good is in keeping the roof from mashing SIDEWAYS. This is where the rear roof area is most vulnerable. The extent to which a roof will mash in this manner is the result of how it rolls, and generally the result of the speed at which it rolls.

"Soft" rolls will not effect it too much, but a flip and roll is much worse. This is where the wheels catch and actually launch the car airborne for a time, when it then lands on some portion of the roof. Even a soft roll at higher speeds - although creating less rotational force - will see the car airborne for a short time. The landing point is most often on the door frame/drip rail area, and the results of this can be significant, given proper circumstance. The top of the windshield area is usually a secondary stress point, and is not generally subject to the high highest loads.

This car rolled on pavement, and the results are clear.


So, are they worthwhile. I'd have to say yes!

smlporsche

^^^ What model Porsche is that John??

analogmike

For a car you drive on the street, I think a half cage is the best you can do. The front hoop is not a good idea on a street car. A good Roll bar with supports going forward across the door will make it very strong and even in the almost impossible event of the A-pillar crushing, your head should still be safe.

DWalker

Also depends on the car. A former GF of mine hydroplaned, flipped, and rolled a Miata at about 70mph. despite sliding on the windshield frame for a bit she walked away without a scratch. At an autocross a few years ago I saw a fellow flip and roll some form of Honda (I think a Prelude?) with a bolt-in roll bar and the A-pillar buckled quite impressively, probably because he slid on it for several yards. Driver got out and walked away. "Modern" cars are specifically designed withthe idea of a high-speed rollover in mind, and the A and B pillars are among the strongest points of the car.

IMHO, a Roll Bar is fine for what it is intended for, IE when the vehicle rolls over- if this is your biggest concern, then a roll bar will do. It does absolutely nothing to help in the far more likely event of contact with another car and/or immovable object.

333pg333

Hmm. This is in a 951 which 'feels' like it's a very solidly constructed car, but....
It is a highly modified street driven car and it will be a very quick car soon with approx 500hp. The events we generally participate in are what we call Super Sprints. This is a timed event on a track over 6 laps where you run in speed groups but not side by side. Overtaking is permitted on straights or if signaled by. The chance of contact with other vehicles is remote. Still, anything can happen.
So the general feeling is a half cage is better than nothing. A full cage is best but there are concerns in a street driven car. Can't these concerns be surmounted?

DWalker

Full cage for you my friend! I have a standardized rant about how the true tragedy is not if you die in a motorsports accident, because then all those who love and care for you mourn a bit then move on with thier lives remembering you fondly. The true tragedy is if you are injured horribly and must spend months or even years in recovery or worse- live out the balance of your life as an invalid. Then all the ones you love and love you in your life have the task of taking care and providing for you the balance of your existence, becoming a financial and physical burden- imagine needing to have an adult diaper changed the rest of your life because you skimped out on a rollcage! I for one, wish that on no one I love! I doubt I am wrong in my guess that you are spending a fair amount of coin building your high-horsepower track monster, and are possibly balking at the idea of spending a fair amount on the safety side of things now. Well, DONT! Spend the money to protect your life and your health.

With good planning and construction there is no issue with a rollcage for a dual-purpose car. Do it right, or buy a Prious.

M758

The issue with full cage on the street is head trauma during a minor front impact from contact of the bare head to the cold steel of the cage. Roll bar padding helps, but steel is very hard and heads are soft.

On track you have a multi-point harness and helmet to minimize that risk.

DWalker

Really? Because in my car(s) with roll cages when driven on the street the 5-point harnesses are used, no OEM belts exist, and all bars within range of the drivers head are covered with padding as per the rules, and to be honest if the debate is going to be increased street comfort VS on-track safety in a 500WHP car the issues are clearly screwed up. Yes, there are lots of 500whp cars out on the street without cages, but they are not turning competetive laps on a track, which is where you are far more likely to screw up and put yourself into serious risk! And FWIW if you arent wearing your belts on the street you deserve whatever you get for being an idiot.

Circuit Motorsports

This is purely guessing right.

No studies have been done to show this one way or the other.

Remember that tehre is some flimsy moulded plastic covering steel at the A and B pillars in cars. I gotta say that some SFI wrapped bars sound a bit better to come in contact wtih than cheap plastic covered Steel. Just my opinion of course.

TRAKCAR

Flying Fin wrote: I have seen you drive; You definately need a cage


My other trackcar is a '01 Mustang GT and I have a "light" (from the roll bar forward 2 bars forward along the roof to the A pillar, down through the dash and 2 bars back along the floor back and 2 diagonally going up to mid level on the roll bar.) cage because it is built weak (Think pudding) and will flatten.

A new GT3 can also crush, but with a techquipment roll bar above my head and sitting with my head next to the B pillars (6'4"), so that all airbags can still deploy, I feel safe enough. These cars are pretty well build.

Still if my car would have come with an RS bar, I would have put the forward part in also, seems drivable enough to me on the street.

The Mustang was also a daily driver, you get used to it.