| Author | Message | ||
| john w. houghtaling, II (Johnhoughtaling)
Junior Member Username: Johnhoughtaling Post Number: 213 Registered: 11-2002 |
I mean: Dennis: Thanks. Very interesting. Like just about every step I seem to take with exotic car ownership, (and racing), nothing is as simple as it first appears. | ||
| john w. houghtaling, II (Johnhoughtaling)
Junior Member Username: Johnhoughtaling Post Number: 212 Registered: 11-2002 |
Dennis: Thanks. Very interesting. Like just about set I seem to take with exotic car ownership, (and racing), nothing is as simple as it first appears. | ||
| Dennis (Bighead)
Junior Member Username: Bighead Post Number: 220 Registered: 2-2003 |
And this too: ====== Walt wrote (and Arne wrote similarly) a note on their thoughts as to why having a roll bar or cage in a street car, and driving it without a helmet on the street might be safer than driving the same street car WITHOUT the roll bar/cage. [Walt's comments are included below my response.] Specifically, Walt wrote, "In a nasty accident on the street your head is likely to hit something anyway. So the question is, how much worse is it to hit a bar than to hit the A or B pillar, or the door window, or the door/roof frame member? Assuming it is a bit worse (the steel tube will be a bit less likely to absorb noggin energy by deforming), won't proper roll bar padding gain that marginal loss back, and then some?" A LOT worse, IMHO. With all due respect, I disagree with Walt's position, certainly with respect to cars designed in the last two decades, and quite possibly with earlier cars too. To be clear, we're discussing head injuries here (helmet v. non-helmeted driving on the street). The position of the roll bar/cage in a given car will vary, but for 911s at least, most are right around the b-pillar and pretty damn close to the driver/passenger's head. Let's look at crashes on the street. The vast majority of automobile accidents are front, rear or side impacts, with rollovers being a relatively rare result. In a car sold in the last decade, nearly every car has front airbags and side impact reinforcement. Some have side airbags. Virtually all have seats designed to protect against whiplash from the rear. In a frontal impact, the driver catapults forward, restrained by the belt (hopefully) and strikes either the front airbag or else the collapsing steering wheel and the crush zones built into the dash. The concern arises if the driver rebounds and strikes the roll bar with the back of his or her head. The same problem if the car is struck from the rear. Or side impacts which might displace the driver. I presume everyone can visualize this and knows of what I speak? Ok, now think about the effect on the head. We're talking multiple g's of acceleration, and the only protection is some foam padding around the roll bar. Ouch. And MOST roll bar padding I've seen is NOT the same as the padding used inside of helmets; glad to hear that you're using the right stuff, Walt. If the bar isn't there, there is NOTHING for the head to strike, Walt - the seatback takes the impact, as designed. The head has many more inches to decelerate, and the impact force is spread along the entire back of the head and almost the entire headrest. Which is soft. Versus the roll bar - the area of impact is basically a small cylinder, so it increases the pressure area on your head. And the amount of deflection to allow deceleration? ZERO. Also, if the head hits the A pillar or window or B pillar, it will hit that component whether or not the roll bar is there! So these other "hits" really doesn't enter into the equation, right? And hitting the A pillar is relatively less common; if you're belted, the belts and the airbag(s) should prevent any a pillar impact from being too bad, if it hits at all. And hitting the windshield or side glass, which can shatter and give, is much better, IMHO, than hitting the roll bar. Bottom line - a roll bar is designed to protect the roof against collapsing in the event of a rollover. A rollover is a pretty rare event, whether on the street or track. Suffering a front, side or rear impact is more likely. Having one's unhelmeted head strike the bar is almost a certainty in a significant front or rear impact. *** And keep in mind, if roll bars really offered any material improvement in occupant safety, wouldn't automakers install them as standard equipment? Wouldn't Volvo be touting its standard rollbar across its model line? Maybe the reason is that automakers have calculated that rollover protection is already pretty good in most cars, and having a roll bar with drivers without helmets only INCREASES the risk of injury? -- if this WASN'T the case, wouldn't ambulance chasing lawyers be using this as the basis for big lawsuits?!?! [obligatory sleazy lawyer content] As I said in my original post, everyone needs to do the math for themselves, taking into account their HEIGHT, the location of their ROLLBAR, and the their own estimations of the likelihood of an accident, and the type of that accident. Just my $.02! vty, --Dennis ______________ Walt's comments: >While I don't think it is sensible to put a roll bar (or roll cage) in a pure street car, and I think it is perfectly sensible to do DEs in a car without either (except for cabs), I don't see a bar or cage as being as much of a detriment for street (helmetless) driving as some do. Here is my reasoning (which is based on the main hoop being far enough behind the driver's head as to be out of the picture, which is the case in my cars): In a nasty accident on the street your head is likely to hit something anyway. So the question is, how much worse is it to hit a bar than to hit the A or B pillar, or the door window, or the door/roof frame member? Assuming it is a bit worse (the steel tube will be a bit less likely to absorb noggin energy by deforming), won't proper roll bar padding gain that marginal loss back, and then some? I use the crushable foam padding on my track/street SC's roll cage where I think my head, or a passenger's head, might strike it. That stuff is like helmet foam: it absorbs energy as it deforms. While it starts out more like a point load (you don't have the nice helmet shell to spread the load), it is also going to deform progressively: more at first, and less as the impact area increases. As far as the softer foam sold as roll bar padding goes, forget it. It will shield your head from discomfort due to incidental contact while getting into or out of the car, but in an impact situation it is likely to do no good whatsoever. So my seat of the pants (or top of the head, if you will) estimation is that on balance I am at least no less safe as far as head injury goes, despite the fact that there are hard steel tubes about an inch and a half closer to my head (with their energy absorbing covering an inch or more closer yet). Of course, I would have to think that, as I drive this car almost every day. </eowalt's> | ||
| Dennis (Bighead)
Junior Member Username: Bighead Post Number: 218 Registered: 2-2003 |
John: Ah, the harness and roll bar issue. Here's what I've written previously on this topic.... As debated furiously on other car lists, the point of contention with regard to safety is that if you're going to use harnesses, you *must* have a roll bar or cage. This prevents injury in situations where the car has rolled AND the roof has collapsed AND the occupant remains belted by the 5 or 6 point harness in an upright position. Injuries could be fatal in this scenario. It's implied by proponents of this scenario that a properly set-up 5 or 6 point harness will keep that occupant firmly planted in the seat where a conventional 3-point stock belt will not, AND that the seat itself will not have collapsed/folded. So let's go with that, for argument's sake. So, does this follow that anyone using a 5/6 point harness in lieu of stock 3 point belts WITHOUT a rollbar is therefore putting himself or herself at greater risk of injury or death? MAYBE. I'm unconvinced. It's certainly possible, but I have not seen any proof. Here's why. For any given safety device, it has benefits and costs. The benefits of a proper racing harness include greater protection in the event of a collision where the car hasn't rolled over -- it keeps the occupant from flailing about inside the cabin and striking things, like steering wheels, dashboards, etc. For argument's sake, let's call this "Benefit One." And a harness also does a better job of keeping the driver planted, so that he/she can maintain control of a car (try doing laps in the same car with and without a harness; you'll find that doing so with a harness will mean that you're not using various muscles to remain seated, and you'll find yourself in better control and not as exhausted). This is especially true if the car is on the edge of control, or if the car has started to go out of control -- if the driver remains planted behind the wheel, he/she has a much better chance of regaining some or full control. So, let's call this "Benefit Two." What about the "cost" to which Mark refers? The possibility that if a car without a roll bar or cage flips over, and if the roof collapses, and if the seat doesn't give way, that the driver, trapped by the harness, will be seriously injured? Let's call that "Cost One." (I can't think of any other costs right now, but am open to suggestions. Also, if the car in question is a street car, someone who drives it on the street without a helmet will likely INCREASE the risk of injury due to striking the rollover protection without said helmet - but we'll leave this out of the analysis below.) So, let's analyze this. Let's assign an arbitrary value to each cost and each benefit. So if Cost One = 50, and Benefit One = 20 and Benefit Two = 20, it would be more intelligent of us to avoid use of a harness without a roll bar or cage. Conversely, if the values were Cost One = 80, Benefit One = 60 and Benefit Two = 50, it would be more intelligent to go ahead and use that harness, even without a roll bar or cage. Again, these values are purely arbitrary. So, what's the point? The point is this -- unless one has a rational basis for calculating values for each benefit and cost, one cannot simply say that using a harness without a roll bar is detrimental to safety. I based my own conclusion on the following observations. Nearly every single collision I've witnessed at the track, or that my friends have witnessed, in the DE environment, has involved hitting something (wall, armco, guardrail, mound, car), sometimes with multiple impacts, but never with a roll over. Do rollovers happen? Of course they do, even at the track. Do rollovers happen that cause a roof to collapse completely? Yes, of course. But not NEARLY as often as impacts without rollovers. In MY cost-benefit analysis, a harness gives me greater protection in impacts (w/o rollovers), and gives me greater control of the car -- thereby reducing my chances of getting into an accident in the first place. Thus, the BENEFIT to me is realized on every single lap, whereas the potential for incurring the COST of a rollover accident where my roof collapses and my seat doesn't and I'm pinned, is relatively LOW. Thus, again, just in my opinion, and for ME, it's actually SAFER for me to use a harness even without a roll bar. ========= First, having a car that doesn't collapse is NOT *necessarily* a good thing. If you had a car built out of adamantium, so that it didn't crush at all, if you had a big impact, you would die. Instead of the car collapsing and allowing YOU additional time/distance (say, 6 feet) to decelerate safely, you'd simply strike the wheel/dash/whatever and have all of 12 or 16 or 28 inches to decelerate from 30 or 40 mph. This is why, starting in the 70s, cars were built with crumple zones designed to FOLD and GIVE WAY in certain places to shift mass away from the passengers and allowing EVERYTHING to decelerate more safely. The passenger cell is still strong and stiff and designed to protect against intrusion. Same concept in, say, a NASCAR race car. The cage protects against crushing intrusions, while the front and rear can and do deform, collapse and breakaway. Second, what protection does a roll BAR afford you? It keeps the car from collapsing if you rollover. It doesn't do much in a front or rear end collision. It presumably affords some side impact protection - but it may worsen the injury too (if an intruding car collapses the side of the car uniformly, it pushes the passenger into the center; if the roll bar resists crushing, and the side impact is offset to the front, might it not allow the intrusion to "pinch" the passenger? Dunno, just thinking about it). Third, a full cage might actually offer significant additional safety, especially if you are shorter or if the roll bar portion is position far enough back so that your head wouldn't strike it. Especially if you run harnesses on the street to help prevent you from flailing about. I've arrived at this sort-of-conclusion because, as stated, I think the risk of a front/side/rear impact is much greater than a roll over, and a cage does offer material safety improvement. Lastly, if you're really concerned, why not just add some roll bar padding to your a and b pillars? :-) thx, --Dennis . | ||
| john w. houghtaling, II (Johnhoughtaling)
Junior Member Username: Johnhoughtaling Post Number: 210 Registered: 11-2002 |
Is it because a person is tied straight upwards into a car with the shoulder harnesses? I can see this. Is this the hazard? | ||
| john w. houghtaling, II (Johnhoughtaling)
Junior Member Username: Johnhoughtaling Post Number: 209 Registered: 11-2002 |
I'm confused. A safety harness in a car is more dangerous than stock belts? I cannot see how. How does a roof come crashing down on a car with safety harnesses but not one with regular belts? If you are suggesting that a roll bar is safer, I agree, but I'm not ready to put a roll bar into my street car. I use the car at 7/10s on the track, and wish not to be sliding around. | ||
| Ben Cannon (Artherd)
Member Username: Artherd Post Number: 846 Registered: 6-2002 |
PUT A ROLL BAR IN IT. You can do leather covered (padded for those withought helmets!) bars these days which look awesome. A harness in a non-caged car is a bit of a safety hazard. So is a non-padded bar withought a helmet and/or good harness... Be careful! Best! Ben. | ||
| Rob Schermerhorn (Rexrcr)
Member Username: Rexrcr Post Number: 795 Registered: 11-2002 |
Dennis has the solution  | ||
| Dennis (Bighead)
Junior Member Username: Bighead Post Number: 213 Registered: 2-2003 |
John, I installed 6-point harnesses in my 355 B by drilling throught the firewall and floor pan. Used massive, high grade washers for the sub and lap belts, and a reinforcing bar behind the firewall to spread the load. The eyebolts for the shoulder harnesses pass through the leather-covered trim piece behind the seats (I have a full hide of replacement material if I should need to retrim them). To make the sub belts work with the stock seats, I came up with a nifty little solution. A good upholstery shop can put a nice reinforced pass-thru hole in your seat bottom, where the adjustable thigh support slides in and out. Thus, I can unclip my shoulder and lap belts for street use, and just stick the sub belt through the hold and under the seat. If you don't want to drill for shoulder harnesses, a good friend had a bar manufactured that mounts where the stock seat belts mount - you'll need to remove the stock reel to install the bar, but you won't need to cut (I think). It may be for sale, as he just bought a Challenge car (he was tired of me passing him in my street car. :-) Call Bob Hatch at Hatch & Sons and see if it's for sale - (508) 358-3500. vty, --Dennis | ||
| Rosso (Redhead)
Member Username: Redhead Post Number: 382 Registered: 12-2001 |
John, I have a freind that has a F355B that had a very nice bar installed behind the seats. It was done by Campbell Auto Restoration, which happends to be right next door to Veloce Speedesign. Contact Tom or Mark at C.A.R at 408-371-5522. They even had the bar painted to match the "palamino" interior and it was very subtle. Good Luck... | ||
| denied (Ragtop)
Junior Member Username: Ragtop Post Number: 51 Registered: 2-2003 |
Isn't installing a harness without a cage a sure way to be sure the roof comes crashing down -directly- on your skull in case of a rollover? Every racer I have ever talked to has said "Don't do it. Its dangerous." | ||
| Rob Lay (Rob328gts)
Board Administrator Username: Rob328gts Post Number: 6192 Registered: 12-2000 |
Hmm, I really don't know John, but here are a few things that may help... My C has 4 "eye hole" mounting points. 2 on the top back shelf and 2 on the back floor. I will attach shoulder straps to top two and other 4 points to bottom 2 with clip on ends. I think finding out how to duplicate this in the street car would be good as you can clip your racing harness out when not using it on the track. The downside is you would have the 4 eyes there all the time. Otherwise without installing new eyes you'll have the most problems with the shoulder harness mounting points. They'll require something very sturdy to attach. When I put a 4 point in my BMW we just used longer bolts on the bottom two points so the street belt and racing harness were installed together. The shoulder points attached to the rear seat belt points, so that obviously won't work on the 355. I say really look into the 355 C mountings and get clip harnesses. I just ordered new sets from Willans and they are 120 pounds each custom made. | ||
| john w. houghtaling, II (Johnhoughtaling)
Junior Member Username: Johnhoughtaling Post Number: 208 Registered: 11-2002 |
I am attempting to intstall a 6 point harness in my 355. Anyone attempted to do this on a street car? Does anyone sell a Bar that mounts behind the seats? I use this car as my daily driver so I do not want anything that I cannot take out, and I'm not ready to put a roll Bar in it. Any suggestions, solutions? John |