Correct, just changed the accuracy of which standards apply; no debate necessary.

Well, had a front tire wash out and went head first into a curb. Helmet saved me a concussion and saved my ear... didn't help much for my lip nose and teeth.

Not unfair or misleading at all, I was actually being technical with my description. According to the government body which defines what constitutes a bicycle helmet, they are defined by how a manufacturer markets a helmet.

CPSC published rules and regs definition of a bicycle helmet, p. 11715:

Yes, a bicycle helmet isn't one unless the seller says it is. That's just reversing the statement that someone can't sell a helmet that doesn't meet the standard. All government rules have some kind of similar statement to define the turf. In this case it ensures that Stetson can't be held to the helmet standard when they sell 10 gallon hats.


But I posted only because the way you made the statement in response to the quoted passage implied that fashion was trumping engineering in helmet design. If that wasn't the intent, consider my post as a minor technical correction and ignore it.

I really could have used some shoulder pads when that happened to me a couple of years ago. Helmet wasn't much use in that one.

That really is close to what the authors intended. They also examined the regulations and standards in some detail. Seriously it's a good read.

maybe a better tire would saved you even more (and saved money on a helmet) :D

Probably time to get a full face helmet. There are some fairly light ones available.

Better than eating with a straw, as they say.

Accidents are not a planned event, unless you are some kind of extreme rider. It sucks, but it happens. Hey, it was a great ride until then...

Ha, I guess at 57 I'm still getting the face I deserve...

Nice save, FB! :thumb: *respectful golf clap*

wphamilton:

I suspect you meant to type 120 to 150 g ?

Joe

curbtender

Your accident is the very kind of accident I claim can happen to anyone. The anti helmet posters here seem to claim their "great bike handling skills" will prevent something like that happening to them.

Some day they will find that their bare head makes a very poor brake pad.

You keep saying this like it makes some kind of sense or is clever. It's not.

mcon

Maybe not clever, but it is the truth!!!

No, strange as it may seem it takes 1200 to 1500 g. 120-150g would be typical for a skull fracture.

For a straight on blow, when the head isn't allowed to move to a side or rotate, it takes much more acceleration for the concussion. But with even an inch movement (instead of fixed) it becomes fatal.

Here is the quote:

In the BICYCLE HELMETS: A SCIENTIFIC EVALUATIONhttp://www.cyclehelmets.org/papers/p787.pdf "One experiment indicated that the critical acceleration to produce concussion was 1500 g. Unlike the experiments by previous investigators, where the head had always been fixed, in some of these it was allowed to move. This resulted in the interesting finding that a blow to a fixed head caused no concussion, though greater distortion of the skull should have occurred, but the same blow repeated with the head allowed to move 2.5 cm resulted in death. "
Rotation (or more precisely angular acceleration), even over a very short arc, is where we get in trouble. As far as severe concussions go.

So what does that mean with respect to the bicycle helmet safety standards? There is a lot of data but not that many rigorous conclusions. Even in the linked evaluation it's noted, "As regards correlation of linear acceleration and degree of cerebral concussion produced, Gurdjian et al. subjected dogs to hammer blows to the head [38]. The results ranged from severe concussion at linear acceleration of less than 100g to none at more than 700g. The authors concluded that no correlation was shown. "

So on one hand we've got 1500g for critical acceleration, and another showing no correlation with acceleration, and standards that assume that linear acceleration is the main factor. What it DOES mean is that for all that is factually known about traumatic brain injury and protection from, there is more unknown or, sometimes, disregarded. For our purposes, our foamy bike helmets are designed to protect against impulse from a direct impact, and little else. Specifically not angular acceleration.

As a matter of fact, there is reference to a test with monkeys in helmets (seems appro to the thread). Six wore helmets, and six wore helmets and cervical collars (limiting rotation). All of the helmet only suffered concussions. None of the collared suffered concussions.

We can go a step further into the almost-unknown. There were more tests about rotations caused by sliding, with the types of helmets we use, at about the speeds we ride. Soft-shell, Styrofoam helmets. Unlike hard-shell helmets, they tended to grab the surface, rotating the head at four to six times the tolerable maximum. Ventilation holes make it worse. Even more disturbing, the added mass of the helmets increase the rotation of a glancing blow.


So people think I'm insane for wanting to reduce the surface area of a helmet, and reduce the mass and cut the lines so that angular deflection is not as likely. Maybe I have a logical reason after all ...

The bike helmet serves poorly for that as well.

pge 156 http://www.cyclehelmets.org/papers/p787.pdf

Hope you all make the right choice for your riding. I'm paying for something I've made a lifestyle. Hey," ain't dead, ain't in jail" as quoted from a friend that can't claim that any more...

Please explain a 300 to 600 degree angle.

30 to 60 with a degree symbol not translated by copy paste. Ctl-F, paste the quote and you'll find it.

You should read the study if you have questions, seriously.

In less than 60 seconds I determined that is 30 to 60 degrees.

if you have enough skill, you can save yourself in any condition


but untill you reach that level, youre gonna have to dismount

RBent, wrong again. :rolleyes:

I guess Felix Baur, Burry Stander, Carla Swart, Frank Guinn, Peter Gunther, Adrian Buttafocchi,

For which a helmet in all likelihood would have not helped. It is a helmet thread after all.