removable roll bars/cages
 

i have a generally poor impression of bolt-in roll bars, or bars that have sections removed by way of a single slide bolt.

however one construct that i have never seen discussed is illustrated in the photo below, and i'm trying to figure out if there is any merit to it.

the tubes will be of adequate (if not more than adequate) thickness, with properly made threads, and the nut made from proper material.

in either case, i can't imagine it being any worse than the slide-bolt designs.

EDIT: i was just talking to a cage buildier and i guess i should clarify that the "GIANT NUT" will be a tube of a foot-foot and a half long, with inside threading. But he says the industry average of "tube in a tube with 2 bolts in different directions" seems to be legit and no body really complains


would like to hear your general comments on the idea

Why not just use a larger diameter tube of approx 8-9" in length to connect them and then have two bolts to hold that in place? Seems easier.

that's the thing about slide bolts

i can be entirely wrong, but arn't the forces then concentrated on that single bolt, rather than being spread over the area of the threaded nut

I'm not seeing the point. Most people with bolt in cages get them because they don't want to permanently weld the cage to the chassis IMO. Do others agree?

This does not solve that problem.

thinking more of a roll bar

you weld in the outside perimeter, but allow the center X to be removed at will.

same for the door reinforcements.

having said that, i think the rollover protection qualities of modern cars are pretty awesome, so i wouldn't be too worried about (considering i won't be doing door to door racing)



EDIT: i was just talking to a cage buildier and i guess i should clarify that the "GIANT NUT" will be a tube of a foot-foot and a half long, with inside threading. But he says the industry average of "tube in a tube with 2 bolts in different directions" seems to be legit and no body really complains

The idea behind the 8-9" steel bar over the joint of the two bars is to help spread the load. In my old bolt in Kirk Racing cage it used two grade 8 bolts. I never tested it (thankfully) but I wasn't too worried.

However in anything but a race car I wouldn't bother with a cage (4 point is fine though) and in a race car I wouldn't bother with a bolt in :)

Why remove the cross brace and diagonal? The reasoning for having those be removable has always escaped me. With a 4 point installed you should *never* have people in the back anyways so access doesn't seem to be that badly needed?

And he's right, that's how mine was, and maybe it was a foot long.. I sold that cage 8 years ago so that level of detail escapes me lol

i never understood the logic behind people being afraid of hitting the steel tubes, i mean if you're gonna hit something, you're gonna hit something (ie, the car's interior wall/glass window/rear window, etc.

plus, it depends on how your route the other components.

but one plus of having the diagonal removed for daily driving is reduced cop attention.

Because people would rather hit their head on a padded piece of soft plastic than a hard steel tube? At high impact the little bit of foam wrapped around the roll cage (which is much closer to your head) does little.

Personally I don't think cages should be in street cars (unless you drive around with a helmet all the time, like the Stig...).

Exactly. The car's interior is a much softer surface that's farther away from you that the down tubes, main hoop, etc are. They flex, the steel bars do not.

Foam on a rollcage won't protect an otherwise unprotected head at all. I used to be one of those idiots that drove a caged car on the street, I would NEVER consider doing so now. Granted I was 23 or so when I did.

As for police attention, even driving a honda and living on one of the main street racing roads (which really sucked ass, especially in combination with what I drove, I had to avoid people following me CONSTANTLY.. fucking dumbass street racers) I never once got pulled over by the cops, even when using r comps, hawk blues that shot sparks out and a side pipe. Maybe cops around me didn't care, but I doubt a rollbar is much of an issue.

Have you ever hit your head, hard, against a steel tube? A rollbar with no helmet and no SFI rated rollbar padding is a recipe for a cracked skull.

SFI padding isn't designed to stop a cracked skull...it's intended to prevent cracking a helmet.

The sleeve & bolt cages are acceptable in most HPDE settings. The threaded coupler looks like it would be a royal pain in the ass to use and is probably less structurally sound than the dual-perpendicular bolts in a sleeve method.

i am i no way denying that

but people die just the same from hitting their heads against windows, steering wheels and interior bits (even if they are designed somewhat to absorb impact)

yes, the cars carcass is designed to flex... when it hits a concrete wall, i question the statement that it is designed to flex when a 20lb sack of flesh is supposed to hit it from the inside.

and will argue that the "foam padding" is in no way worse than the 2mm plastic used to wrap around the interior of your car.


having said all that, i have been participating in motorsports for over 6 years and am still driving stock (see sig), however there are times when i think about my safety a little too much and start thinking of something along the lines of a roll bar... :thumbsup:

Yes people die from everything. That doesn't mean that INCREASING the odds of someone dying because of your poor judgement is acceptable though.

I'm all for safety in motorsports, just not at the expense of others who happen to be in your car.

Any sort of roll bar = no more rear passengers. Period. Also, you're not going to want to be installing and uninstalling it, especially with no rear doors to get access. It's good that you can remove it at some point in the future as opposed to a weld in, but with a roll bar, your car's essentially track dedicated and you won't want to drive it anymore. Especially since you'll probably be running harnesses and racing seats. Ask me how I know.

Firstly, I don't think there's a lot of point in caging a car unless you strip it back to nothing and weld in a proper cage and further think that once you are considering a weld in cage, you should also be considering a dedicated race car.

However, the bolts that hold a joining tube are not there to provide strength in an impact. It is the overlap of the two tubes that provides the strength. The bolts just hold the tubes in place, but aren't even needed once impact forces are applied.

If you are considering your safety, and thinking "rollbar" you should be thinking "complete safety package." By that I mean: SFI/FIA seat, SFI/FIA harness, head and neck restraint _AND_ a roll bar.

No one piece of that is much good without the rest.

A roll bar in a four-seater means you now have a two-seater. And, if you put a roll bar in your now-a-two-seater, you need to have equal safety gear for the passenger...so that "complete safety package" now requires two SFI/FIA seats, and two SFI/FIA harnesses.

As usual I agree 100% with the above.

I'm greatly anticipating the car to come out. Not because I'm going to buy one right away, but so we can finally get a dedicated motorsport subforum on here.

In general I agree, but not everyone is wheel to wheel racing in sanctioned events and is going to shell out a few grand for a rulebook spec weld in cage. With the speeds I hit and experiencing my first high-speed spin/off, I just wanted more safety on the track. Like everything, it's all a compromise.

I'd only say that a roll bar is fine without the rest.

Yes, which is why I wrote and instead of or.

Your statement sounded like the sfi padding made it safe.

I'd disagree. I'm on my iPad do I don't feel like typing it in detail again but collapsible seats and 3 point harnesses really shouldn't be used with a rollbar.

That was not my intention.

And if you tested that theory of yours you'd find out how very wrong you are....but you'd probably be dead or a vegetable so it wouldn't matter to you.

That may be true, but there are cars that come with harnesses that do not have roll bars (or perhaps it is built into the actual chassis, so there is no apparent roll bar), and there are cars with factory roll bars that does not come with harnesses.

Marginally more safety at the track (debatable) plus less safety on the street (no helmet) for front-seaters and enormously greater risk for rear-seaters (enough more that rear seat removal is warranted) is what you're considering. This car is going to provide a fair amount of rollover protection without a roll bar. My advice: forget about installing a roll bar.

Why would you need a helmet on the street with a 4 point rollbar? Also, I already stated that rear passengers are non-existant with a rollbar. It's not something I'm considering, it's in my garage right now.

I didn't say "you need a helmet on the street with a 4 point rollbar", I said "less safety on the street". I.e., any tiny reduction in risk due to marginally greater rollover protection is likely offset by the (probably) less tiny risk of whacking the rollbar with your head in a greater number of types of accidents, including many more likely than rollovers.

FWIW, my Z, RX-7, and S2000 street cars all have 4-point roll bars. In the Z (minimal rollover protection stock) and the S2000 (convertible), they *might* be all-around safer street cars with the bars. For the RX-7, probably not, but required for its classification for track days ("prepared"). Otherwise I might remove it.

Anyway, I'm not jumping in and saying you MUST remove roll bars from street cars. I *am* recommending against installing a 4-point bar in a street car that already gives reasonable rollover protection. Costs time/money/effort and in all likelihood you'll be a smidge *less* safe for most of your usage.

Yeah, like I said, adding a roll bar makes the car all but un-streetable. Mine's a purpose track car but not a race car, so I can still drive it to and from the track but don't do much else with it because it's so unpractical.

I guess the bottom line is do seats and roll bar and harnesses or none at all. But doing it will make the car less enjoyable a lot of the time and probably won't be your daily.

roll bars are never a good idea for a street car. not ever

what about factory built in roll bars :bonk:

still a bad idea. besides the only factory roll bars i can think of come in those stupid fast porsches that are designed for the track whether they are driven there or not

http://www.nasaproracing.com/hpde/rollover.html

So what you are saying with that is that you finally agree with Dave and me? Because "proper safety equipment" is a a seat, a bar and harnesses.

And the part pf that post you left out:

Curious, what cars come stock with roll bars, collapsible seats and three-point seat belts?

yeah well if you read that you will notice that they are talking about taking a convertible to a track. since with a convertilbe you have to have some sort of roll protection, a roll bar is the minimum required amount but it even says that the roll protection in a newer convertible such as the s2k may be enough. this has nothing to do with what is safe on the streets. it is about how you must meet the requirements of a track to drive on a track

No, they mention the SK2 as an example. That article is not written about convertibles.

And as I've said, once you add a rollbar/seats/harnesses, the streetability of the car is gone. Why you're hung up on this setup to the grocery store is beyond me when it was installed for track safety.

Yes, and that is what I run (so long as by bar you mean roll bar and not harness bar).

i simply assumed that this was in regards to a multipurpose car. otherwise why would you ever need anything removable as far as the roll bar/cage is concerned? and yes that part about the roll bar looks to be about convertibles since it said that all you need is a helmet unless you have a convertible, then you need a rollbar.

I've got a rollbar in my miata. After fmic, boost gauge, and intake I had to. Could I smack my head on it? Yes. Could I roll the car and it save me? Yes.
If I get hit hard enough for me to hit it and not live there probably wasn't much that would have saved me. It has no padding and probably won't.
There will always be 'what ifs' but until those happen I'll enjoy the extra chasis rigidity and how sweet it looks.