Roll bar safe for street? Is one safest?

[Earendil]

With my E30 retired from DD work, it is now a weekend and HPDE car (with aspirations of Pro-3). I've read around here and come to accept that race harness and seat are not safe unless a cage is installed, or at least a roll bar is installed. As much as I don't want to slide around, I can deal with it and buy a good race seat at some future time. But right now, my budget probably allows for a Kirk or VSR roll bar. Two questions for you guys, as seen in the title:
1. Do the Kirk and VSR bars sit far enough behind the front seats to make the car safe to drive on the street without a helmet?
2. Is one bar safer for the street than another?

Most of the picture I can find of them in E30s look to sit plenty far behind and high. But perhaps someone that has one could give me some feedback. Cheers!

[jlevie]

In my opinion the advisability of this is a function of the cage, the seat, the harnesses, and the driver's size. I'm not real tall (5'8") and I have a RaceTech halo seat mounted really low with 6-point harnesses. The cage is a Kirk weld in pushed as close to the skin of the car as possible. On the street there is pretty much no way that my head can get close to any part of the cage. So I feel completely comfortable in the car on the street.

But if I were taller, used a non-halo seat, had the seat mounted higher, or had a bolt in cage my opinion of how safe that was would be different. A disadvantage of a bolt in cage is that it winds up further from the skin of the car and thus closer to the driver. And if you don't remove the sunroof and cassette even a weld in cage is closer than desirable.

That doesn't directly answer your question, but that is because the answer depends on what the whole consists of.

[cosm3os]

J's on the right track, but I would add that you would be shocked how far the body moves in an accident, so don't rely on how much clearance you have just sitting in the car in the driveway.

[Earendil]

In my opinion the advisability of this is a function of the cage, the seat, the harnesses, and the driver's size...
...So I feel completely comfortable in the car on the street.

But if I were taller, used a non-halo seat, had the seat mounted higher, or had a bolt in cage my opinion of how safe that was would be different.
...
That doesn't directly answer your question, but that is because the answer depends on what the whole consists of.

That is helpful, thanks. I knew it would be a function of more than just the chosen roll bar. Perhaps I need to just find someone that has one of these bars installed with stock sport seats and get them to let me sit in it, see where my body ends up at. Of note, I will not be installing a cage, bolt or weld, in my car until it is a dedicated track car where I will be wearing a helmet the entire time. Having metal bars around my head in an accident does not excite me in the least :down:

J's on the right track, but I would add that you would be shocked how far the body moves in an accident, so don't rely on how much clearance you have just sitting in the car in the driveway.

I was in a 5mph wreck once (lady pulled out in front of me) and I was extremely surprised at how much force that was. So I can only imagine what happens in a real wreck. That said, some of the locations I'm seeing these bars tells me that if my head ever goes that far back, something else must have gone terrible wrong. For example this picture of a Kirk bar



Assuming for a second that my seat sits at the same distance, it seems like for my head (and body) to have departed that far from my seat, I have other issues.

Thanks for your input guys. Maybe someone will bring an E30 and a roll bar to the next HPDE, so I can take a good look.

[shiftbmw]

Assuming for a second that my seat sits at the same distance, it seems like for my head (and body) to have departed that far from my seat, I have other issues.

You need to remember that a car chassis deforms in a collision. The closer your seat moves relative to your roll bar, the less distance your head has to travel.

Harness, Fixed back Seat, Roll Cage, and Helmet always go together. To omit any of those things is to compromise your safety...

[Dave]

I had a kirk bolt in roll bar and now with the car gutted, have a custom made weld in roll bar. The new one definitely is much higher to the roofline than the Kirk, and my seats sit pretty low. I'm only 5'10".

Having said that, I covered both bars with the high density (not that pool noodle looking stuff) roll bar padding. And I only drive the car to and from events - and yes - this is still a compromise.