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Been decades since I owned a car with a roll cage. Back in the day, we took our car to a roll cage builder that someone "knew" and he welded a cage into the car. We hoped like hell we never needed it and mostly we didn't. It was "better" because it was a bunch of tubing where there was no tubing. Must be stronger! Must be safer! We've got more steel!!
Then we saw racing change and the advent of better safety devices and what we knew about safety changed.
I get that "experienced" builders of roll cages have experience, but other than anecdotes is there testing done? How? Have we advanced past the point of "they build bars/cages and we've got more steel, it must be better?"
Do we know the safety of bolt in bars? We've got half a dozen vendors selling bars for the GT4, how do you decide if that bar is worth it? Its great that we can power coat them and hook belts to them, but misses the point, I think. Do the damn things work?
iirc the NHRA used to look for a sticker [SEMA?] on the roll bar ....if it didnt have a sticker you could not run. now days it can be up to the event holders.....you will not need a bar for acme supermarket empty parking lot course but neither did i need one at VIR in my corvettes and we were over 155 mph.start with looking up racing organizations and their required specs on bars and how they are certified.
Hopefully this does not degenerate into a conclusions that it's better off to stay home wrapped up in a bubble suit.
Gee, I hope not.
However, the discussions about carpet cutting and power coating are a bit misdirected if we care about safety.
I trust we agree that safety belts and good helmets are useful and that a good roll bar/roll cage might be helpful. I'd rather decide based on some data rather than the color of the bar.
Are the roll bars well made? Are the anchor points secure?
Not all the people who suggest welded in bars rather than bolt in bars are people who own welders!
I've not paid much attention to this in years, there must be collective wisdom?
However, the discussions about carpet cutting and power coating are a bit misdirected if we care about safety.
I trust we agree that safety belts and good helmets are useful and that a good roll bar/roll cage might be helpful. I'd rather decide based on some data rather than the color of the bar.
Are the roll bars well made? Are the anchor points secure?
Not all the people who suggest welded in bars rather than bolt in bars are people who own welders!
I've not paid much attention to this in years, there must be collective wisdom?
You race Shake, what say you?
I don't race anymore, I wish I had the time to make it work with 3 kids. To be honest, it's a lot more fun than 3 kids are sometimes, and a lot more fun than HPDEs. I think an easy place to start the conversation is what products out there could serve in some capacity as roll-bar, vs a pretty metal human skewer. A few of the more experienced manufacturers/vendors call their product what it is - a harness bar, not a roll bar. There are only a couple, and specifically one, that, IMO, has the knowledge, experience, and justification that their product would serve in some capacity as a bolt-in roll bar.
Bolt in rollbar/harness bars won't hold up. Bolts will shear and they will collapse. True roll bars are welded to the chassis.
There's got to be data on this. There's enough DE cars around and enough accidents at the track to say what ratio of cars with bolt in bars have the bar perform as intended.
Real race cars go through considerable expense to weld the cars in, including the GT4 Clubsport. In fact, in cars with aluminum or carbon chassis, sometimes you will even see the roll bar plates glued in place in addition to being bolted.
For this reason, I've always assumed they are more safe, but I cannot quantify it.
There's got to be data on this. There's enough DE cars around and enough accidents at the track to say what ratio of cars with bolt in bars have the bar perform as intended.
I can't find it. I've been looking. It seems that the NHRA does the best job writing their specs and to my layman's eye....the most stringent guidelines, but I can't find any data.
I think its an important question. These cars run at high speeds and I have to say the idea of bolt in bars makes me anxious. I'm not going to race anymore, I'm old enough and I don't care anymore, but I still think it is an important discussion.
We've got some real expertise on these boards, hopefully one of the experienced guys will chime in. I may poke at the 993 forums as there seems to be more "real" racers there, not just doing DE's. That said, I'm thinking that I might just find one of the really experienced builders to weld bars into the car. That's why the questions.
Be interesting if some of the bolt in bar builders chimed into the discussion. The idea is not just to anchor the seat belts, but to protect us, no? These are real race cars in a lot of situations...the speeds are far higher than what we used to run.
I really have no idea how safe the bolt-ins are...I do know that welded in bars don't cost an arm and leg more.
FWIW, here's the PCA Club Racing roll cage specs, which permit bolt in cages:
APPENDIX A - ROLL CAGE SPECIFICATIONS
Roll Cages: The roll cage must be securely mounted with the mounting plates at the bottom of the hoops mounted directly to the floor and/or longitudinal members of the unibody and make metal to metal contact. Any padding, carpet, upholstery, etc. must be removed to satisfy this requirement. The mounting area of bolt-in roll cage must be backed by a plate of a size equal to that of the upper mounting plate with a minimum thickness of 3/16”. Bolts must be grade 5 or higher. The roll cage must be full cockpit width, except as originally supplied by the factory for open racecars, and have two fore/aft tubing braces. The braces must be mounted as near to the top of the main hoop as possible at an included angle of at least 30 degrees. Also, the assembly must contain a diagonal (left to right side) tubing brace from one upper side of the main hoop to a floor or unibody lower frame mounting point of a bar member on the other side to obtain the strength benefits of triangulation. Roll cage bar tubing in the Stock/Prepared Classes must remain within the passenger compartment. The removal of the door glass to facilitate side impact protection is allowed. Carbon fiber roll cages are not allowed.
The roll cage must have a full width main hoop and a full-width front hoop or two side halo hoops around the door opening connected by tubing across the top of the entire windshield. The tops of the hoops must be as close to the roof as possible in closed-top cars. In open-top cars, the top of the main hoop must be at least 2” above the driver’s helmet, and the plane formed by the top of the main hoop and the top of the front hoop must be above the driver’s head in both closed and open top cars. The front (or side halo) and main hoops must go to the floor pan and be connected with each other with tubing as close to the roof line as possible. The cage must have at least one additional bar across the door opening below the window level on each side connecting the front and main hoops for side impact protection. Additional side impact protection (two bars or “NASCAR” style bars protruding into the door) is strongly recommended.
An inspection hole 3/16" in diameter must be provided in a non-critical area for verification of tube thickness. Any portion of the assembly which may come in contact with the driver’s helmet must be covered with high density foam at least 3/4" thick held securely in place with zip ties, electrical tape or duct tape. Foam must be equivalent to SFI 45.1 or FIA 8857 standards for hardness.
Minimum Roll Cage Tubing Sizes
All required tubing must have the following minimum diameters and wall thicknesses:
Car Weight without Driver
Under 2500 lbs. Over 2500 lbs.
Mild Steel 1.50" x .095" 1.75" x .095” or 1.50" x .120”
Alloy Steel 1.375 x .095" 1.50" x .095"
Factory Roll Cages as delivered in factory race cars are allowed. Roll cages sold or installed by Porsche in street cars are allowed in stock class cars if certified to meet FIA regulations.
I don't know if there is a ton of data out there on rollovers at HPDEs but there are definitely some great examples of what not to do....
Bolt-in or welded I think matters less than actual design of the bar as far as materials, strength, and mounting points. As per the two examples above, having a really strong bar mounted to points that aren't reinforced or intended to be load bearing is just as dangerous as a bar that is solidly mounted but not designed to support the G forces of two people and seats.
All the bolt-in bars I've seen on the forum advertise themselves as HARNESS bars and make no claims to provide roll-over protection. Why so many of the designs seem to have main hoops I don't know, maybe just cause race car?
The real question for the OP is if you're looking for a place to mount a harness or if you are looking for actual rollover protection.
FWIW, my decision process was the following:
1. My GT4 is not a race car
2. I don't wear a helmet or strap into a harness on the street to prevent me from potentially smashing my head on a steel roll hoop
3. I'm comfortable with the compromise of having LWBS seats + harnesses without rollover protection
1. My GT4 is not a race car
2. I don't wear a helmet or strap into a harness on the street to prevent me from potentially smashing my head on a steel roll hoop
3. I'm comfortable with the compromise of having LWBS seats + harnesses without rollover protection
so I got the RSS bar...
Our local HPDE organization requires roll-over protection if you use a harness (using the logic that a harness doesn't allow you to duck if your roof collapses).
Point 2 is one that I took to heart a long time ago. I've been a Miata owner for more than two decades (same car the whole time, for the record) and there's still a raging debate r.e. whether to install a roll bar on a street-driven car. Camp one trots out scary photos of rolled Miatas sans roll bar, with completely flattened A-pillars. Camp two (into which I fall) points out that roll-overs are relatively rare events, especially for a car with such a low center of gravity. The bigger risk is being rear-ended, whereby you're almost certain to clang your noggin on some pretty unforgiving steel. Even proper roll bar padding isn't a panacea, as it's designed to work in concert with a helmet.
Regardless, I wanted to track my Miata, and that wasn't in the cards without proper roll-over protection. I worked with Flyin' Miata and had a one-off removable roll bar made for my car. I can bolt it in in less than an hour, drive to my event and then remove it in about the same amount of time once home. If I could keep transmissions in one piece, I'd still be tracking it. On the topic of bolted-in vs. welded: For Miatas, at least, a good 6-point bolted-in roll bar appears to hold up as intended.
To be fair, there are cage welders that don't know what they are doing. Some builders base their cages on old styles or their days of dirt track racing or some other class of racing. I have seen all styles too, from guy in the garage to the pro shop and they all look different and sometimes questionable. I have also witnessed a number of cars crash with both welded cages and bolt-in cages. Both styles have provided the support to allow the driver walk away without any issue. The crashes I have seen ranges from rollover (one roll) to all sides leading the impact (head first crash, rear first crash, quarter first crash).
In the end, a well-made bolt-in could work as well as a well-made welded roll/harness bar. There is always a change something freak could happen, but at the end of the day some form of safety is better than no safety. It will probably come down to what the owner "feels" is safest for them.
The reason its hard to find information on this is out of respect. When at the track most people will see the incident but out of respect for the club and owner, pictures are not taken or shared. But if you go to enough track events for a long enough period of time, you'll be able to draw your own conclusions.
06-16-2016, 01:23 PM
Safety of bolt in roll bars/cages
