Motorcycles

[Oberon]

I can say with some confidence that if you wreck while pushing a modern sportbike near its limits on public roads, the primary purpose of your helmet is to ensure that when your head is found, it will be readily identifiable.

[Jack Flak]

Originally Posted by Oberon

I can say with some confidence that if you wreck while pushing a modern sportbike near its limits on public roads, the primary purpose of your helmet is to ensure that when your head is found, it will be readily identifiable.

The same holds true for car bodies as helmets if we're really talking limits.

[spirilis]

Motorcycle helmet - Wikipedia, the free encyclopedia
Standards testing

Most motorcycle helmet standards use impacts at speeds between 4–7 m/s (9–16 mph). At first glance, this is confusing given that motorcyclists frequently ride at speeds higher than 20 m/s (45 mph). This confusion is relieved by understanding that the perpendicular impact speed of the helmet is usually not the same as the road speed of the motor cycle and that the severity of the impact is determined not only by the speed of the head but also by the nature of the surface it hits. For example, the surface of the road is almost parallel to the direction the motorcyclist moves in so only a small component of his velocity is directed perpendicular to the road while he is riding. Of course, other surfaces are perpendicular to the motorcyclist's velocity, such as trees, walls and the sides of other vehicles. The other vital factor in determining the severity of an impact is the nature of the surface struck. The sheet metal wall of a car door may bend inwards to a depth of 7.5–10 cm (3–4 inch) during a helmeted head impact, meaning that it generates more stopping distance for the rider's head than the helmet itself. So a perpendicular impact against a flat steel anvil at 5 m/s (11 mph) might be about as severe as a 30 m/s (67 mph) oblique impact against a concrete surface or a 30 m/s perpendicular impact against a sheet metal car door or windscreen. Overall, there is a very wide range of severity in the impacts that could conceivably happen in a motorcycle impact. Some of these are more severe than the impacts used in the standard tests and some are less so.

The speeds are chosen based on modern knowledge of the human tolerance for head impact, which is by no means complete. It is possible to deduce how well the 'perfect' helmet outlined in the Function section of this page would perform in an impact of a given severity. If currently available data suggest that the rider is unlikely to survive in such an impact, regardless of how well his helmet performs, then there is little point in demanding that helmets be optimized for this impact. On the other hand, if an impact is so mild that the rider is unlikely to be injured at all so long as he is wearing a helmet than that impact is not a demanding test. Modern standards setters choose the severity of the standard test impact to be somewhere between these two extremes, so that manufacturers are doing their best to protect the riders who can be helped by their helmet during a head impact.


^ the velocities cited there I saw elsewhere: http://www.bikersrights.com/statisti...goldstein.html

So the tolerance is actually ~9-16MPH on the helmet itself, which means you're bound to be severely injured if you hit a surface perpendicular, but not nearly as bad if you're moving predominantly parallel to it (i.e. falling to the ground and sliding). In fact, assuming you never come perpendicular to any objects (and just slide), the actual speed might not matter much with a sliding impact. The rest of your gear might determine fatality moreso in that scenario.

[Oberon]

Originally Posted by Jack Flak

The same holds true for car bodies as helmets if we're really talking limits.

Oh, I don't know. Provided that you're strapped in, the airbag deploys, and you avoid major obstacles like bridge abutments and oncoming semis, your odds of survival are pretty good.

Admittedly, that's a great many caveats. Best to avoid the situation altogether.

[Grayscale]

Originally Posted by Oberon

I can say with some confidence that if you wreck while pushing a modern sportbike near its limits on public roads, the primary purpose of your helmet is to ensure that when your head is found, it will be readily identifiable.

i disagree... statistics show that in about half of fatal motorcycle accidents a helmet wasnt worn. the common other contributors are speeding, drinking, and lack of proper training.

the majority of motorcycle accidents are not fatal, it really depends on the accident, though. the only major risks to someone who is wearing all of the proper gear is a high-side crash or being struck by another vehicle, everything else is quite survivable. most crashes are low-sides and as long as they are not run over by a car, then the friction created by sliding on the ground usually slows them down enough so that smacking into a divider isnt deadly if the rider isnt speeding excessively.

with that said, there is always guys like this one who crashes through taco bell at 150 mph... i guess the drive-thru wasnt going fast enough. basically, just dont act like a retard, like popping wheelies through rush hour wearing a t-shirt and jeans, you'll probably be okay, and on the safer side of the statistics.

[Oberon]

Originally Posted by Grayscale

i disagree... statistics show that in about half of fatal motorcycle accidents a helmet wasnt worn. the common other contributors are speeding, drinking, and lack of proper training.

...but our statements are not in opposition to one another.

[Grayscale]

if im not mistaken, you are saying that a helmet will not make a difference in a high speed accident, i was pointing out that the correlation between fatal accidents and the rider not wearing a helmet would suggest otherwise.

there are also plenty of accidents in professional motorcycle racing where the participants dont get broken into hundreds of little bits.

if you hi-side at that speed, though, yeah, helmet is probably just a head bucket.

another big problem is motorist awareness. because most people who drive cars have never ridden a motorcycle, they dont "relate" to the visual and are actually less likely to notice them. thats when they pull out into an intersection and whammo, the rider takes a short flight over the hood. thats the sort of thing motorcycle riders have nightmares about.

[kyuuei]

I've been scared of them for a great portion of my life, so I've made a personal goal to get one and overcome that fear of them by taking the time to learn and ride one.

So! I suppose after I buy my house that'll be my next financial investment.

[Anja]

Originally Posted by Jack Flak

Hmm. I take issue with some of that, but I'm not quite in the mood for extensive research. Are you sure you're not talking about CPSC rated foam bicycle helmets instead of DOT approved motorcycle helmets?

We were active in ABATE (American Bikers Aimed Toward Education) for a number of years. And unless they are making motorcycle helmets differently those were a couple of facts that our lobbyists in Congress used to oppose a mandatory helmet law. It could have changed, Jack. I know there are strong arguments on both sides and I'm too lazy to go researching, too.

I think just leave it to the individual. Darwinism.

[Jack Flak]

I'm almost always on the side of freedom. I don't believe helmet laws should be mandatory...But to say they probably won't save your ass if you wreck is taking it a bit far.