License2Ill

What are you asking? Or what are trying to say without having info on it?

The EPS and plastic shell in a Snell-certified bicycling helmet works over a range of impacts from a 0 meter fall to a 2.2 meter fall to the flat hit with a head in the helmet. Are you missing other foundations in the ideas of a head in a helmet hitting a surface from a distance?

a. For each impact against the flat anvil, the impact energy shall be 100 J for all testing regardless of headform size or weight. Given an ideal frictionless mechanical test facility, this impact energy represents a 2.2+ meter drop of a 5 kg headform and supporting assembly.
b. For each impact against the hemispherical anvil, the impact energy shall be 65 J for all testing regardless of headform size or weight. Given an ideal frictionless mechanical test facility, this impact energy represents a 1.3+ meter drop of a 5 kg headform and supporting assembly.
c. For each impact against the kerbstone anvil, the impact energy shall be 58 J for all testing regardless of headform size or weight. Given an ideal frictionless mechanical test facility, this impact energy represents a 1.2 meter drop of a 5 kg headform and supporting assembly.

Six jours

Hopefully by "you guys" you mean pretty much every cyclist in North America.

Otherwise, you'd appear to be blaming this one thread for the strongly held opinions of, well, pretty much every cyclist in North America. And that would be kind of silly.

RaleighSport

Ehh I was just referring to the people passionate enough to troll helmet threads to spout their same crap they do in any other helmet thread, I was thinking to myself earlier what a loss it is people can't really ask for advice without having a heated battle appear, not trying to swipe a giant brush here and paint eveyone, I'd go so far as to say it's an extreme minority.

I-Like-To-Bike

"Spout the same crap"? Does that mean information, facts and/or opinions with which you disagree, and therefore should not be posted?

License2Ill

I think the frustration comes from the matter-of-fact opinions that get spouted by those that clearly don't really understand what helmets are, what they are supposed to do, and what they actually will do at any point, followed by a statement about how their opinions are supposed to be informed due to a lifetime of a lack of info that took years to accrue. Cutting through all that, it just becomes clear again that properly certified helmets are a good idea regardless of what some bone head has to say about them or the gov't.

RaleighSport

Probably more eloquent than I would have written it, but I have to agree.

3alarmer 

FWIW, I don't think your giant brush is that bad of an idea. Most of the guys left here are basically here
to voice the same points and opinions they've been posting here for quite a while now, and I notice the usual
suspects appear every time someone new shows up to point out the logical fallacies regularly espoused
by the helmentless. When you carry on a crusade long enough, most of the more sensible tend to drift away.

At risk of stating the obvious, this thread is now on page 232, and guys like i like to bike and razr skut are still
happily trolling away at every appearance of a logical pro helmet position, while giving voice to their absolute
dedication to the thread's "progress". It's inspirational, in an obsessive compulsive sorta way.

digitalmouse

Agreed. I'm not anti-helmet, but I am generally anti-stupid. Having lived in Europe for 13 years now, (7 years in Germany, and 6 years in Copenhagen, Denmark, arguably one of the top cycling cities in the world) it's pretty clear that the stupidity lies in Helmet *promotion* as the panacea of cycle safety - where Helmet producers, skewed studies, and politicians sucking up to the people keep you off balance by presenting outdated, outmoded data, opinions, and anecdotes as facts.

It's pretty clear (at least in Europe, where the daily cyclists outnumber their North American counterparts at least 100-to-1) that using your head is far more effective than protecting it blindly with an object that is good against the occassional tire-thrown stone, fair in minor spills below 10 kph, and pretty useless in anything above 20 kph (the typical cruising speed of most Danes in the city), not to mention getting struck by a car/truck.

It's pretty clear through numerous studies, news reports, and cases that as cycling increases, the number of injuries (with or without helmets) doesn't grow proportionally or increase in severity. In fact, the more people cycle, the more that vehicle drivers pay attention, and the less chance of accidents (usually of the 'I didn't see you in my mirror' variety). It turns out in Europe that the more that people cycle, the safer cycling becomes.

In several countries around Europe, helmet laws were struck down in large part due to the populous getting the politicians to do the right thing: let us decide if we want to wear a helmet or not. The right to choose is far more important than the debate on whether the helmet actually does good or not. Let the sheeple wear a helmet or not - but let them choose.

Earlier on, someone in this thread posted something along the lines of "raise your hand if you ride without a helmet and have not had an accident in the last three years". That's biased from the start, and makes it sound like people should be having accidents or you are not "real men". It would be more important to say "raise your hand if you ride and have not had an accident in the last three years" -- ok even that has bias. Hmm.... Best version should be "raise your hand if you ride", as using your head to stay aware of your surroundings (like the Marines: "keep your head on a swivel") works far better than blindly relying on a helmet with questionable design specifications. Get out there and ride! Wear a helmet if you want to, or not, but ride!

And for the record, I've not had an accident while cycling in 20 years. And I don't wear a helmet - unless you count my baseball cap to keep the sun out of my eyes. In the last 7 years I've been riding recumbents and velomobiles on a daily basis for work, play, and holiday touring (comfort, weather protection, and speed - oh my!), and you would think that being lower to the ground would invite accidents or increase my chances of getting into one. Turns out to be a myth. Being on a recumbent or in a velomobile makes me even more visible because I stand out against the sea of cyclists. My seating position also gives me a more level-headed view (literally) and with the use of mirrors on both sides I have an excellent awareness of my surroundings. *If* there ever was a need for a cycling safety *law*, then it ought to be the use of mirrors. Every other fast moving vehicle out there uses them, so why not cyclists too? I bet that would reduce accidents faster than helmet law use.

RazrSkutr

What I am asking is for you to supply the information which you claimed you had on the general usefulness of bicycle helmets for saving us from certain death. You were quite explicit on this point, and if it's true then we should all be wearing helmets. Specifically, in this post I argued that EPS can absorb energy, but that that range rarely occurs in the situations which give rise to the absolutely fearful injuries which you mention.

You have, at length, argued against this. No one is arguing that in the perfect, tiny fraction of real-world values for which EPS drop tests are conducted that energy absorption does not occur...

SNIP irrelevant quote from Snell standards.

mconlonx

Personally, I'm just glad that License2Ill, RazrSkutr, and Chasm54 all found each other. Dueling desultory studies and abstracts.

I was the one who posed the "Raise your hand" helmet/accident question, and it was more about finding out how many have crashed and what their injuries were. We hear all the time from the helmeted proselytising about how they fell off their bikes and a helmet saved them from death; just wondering what kind of accidents the unhelmeted have suffered. Only odd thing in the responses is that no one pointed out that all of those dead or comatose because they weren't wearing helmets can't answer...

License2Ill

Energy absorption is not what is occurring in a crash helmet. The EPS is slowing the rate of acceleration as it crushes by applying a braking force to the head. I'm not sure where you get this tiny fraction of real world values from. The range covered by a 100J hit include a drop from over 2 meters at the speed of gravity against a flat surface, and slightly less for more pointed surface hits in terms of tested capabilities. Without a helmet these impacts will provide more than 300g to the head. Hits above that level at some point will also provide more than 300g, but from the injury data in the various links presented, those impacts were from falls in that range. The motorcycling DOT standard actually uses 400g as a benchmark, but the time requirements basically mean the helmet will achieve lower than 300g which is the accepted amount by all other standards. I don't know where the specific info on the 300g limit and that history can be found, but I know Ed Becker of Snell will be quick to provide that for you if you email him about it.

I think I may have found the link I thought I had with the implications link I provided earlier, this is the one I was looking for: https://smf.org/docs/articles/helmet_development

Are you simply trying to argue that falls on bikes don't occur that create 100J of impact energy, or are you saying that falls on bikes routinely create more than 100J impacts to the head? This isn't a valid question, it's not a matter of how often the head hits anything or how often the falls occur, it's a matter of protecting the brain through the largest range possible that will be accepted in terms of size by the community, and limited by materials capabilities and technology to fit those size and ventilation requirements, which can be minimally standardized.

From the data in the various studies of bicycling helmets and motorcycling helmets that the helmets will work. Recent criticism of motorcycling helmet standards even goes so far as to point to DOT limits as providing better results by being softer, according to head injury data for motorcyclist accidents. That only points more to the bicycling helmet range as being more appropriate with the injury data surrounding that research. I, however, will go along with the idea that bicycling helmets should be expected to be better than what current standards achieve, especially the CPSC standard. The industry has fought to only have to comply with a low standard of protection to allow for features to be sold over substance. That's why I'll only buy a Snell-approved lid and wish more manufacturers would get with it. It doesn't appear that Snell can raise the bar any further either as long as CPSC is so dominant in the market and cyclists continue to throw their hands up in the air with an sigh over it. The fact is that the money is in sponsored rider paint jobs, and not in building helmets to comply with harder to achieve protective levels. When riders are buying based on the vent count, the aero look, or the jersey associated with the paint on the shell, not much is likely to change.

chasm54

A study can't be desultory. We can use studies in desultory manner, but that is quite different. Try to live up to the intellectual standards of the read.

I'll refrain from pointing out that for most of the dead or comatose, whether they were wearing a helmet probably made no difference...

The problem with License2Ill's very cogent arguments is that they do not seem to be borne out by real-world experience. I have no problem accepting that helmets absorb energy as demonstrated in lab tests. But out here where we cycle, increased helmet use does not appear to result in a reduction in serious injury to cyclists. So it would seem that helmets work as intended, but work within parameters that don't make much difference to our chances.

License2Ill

I guess you're the one that posted the abstract to the Rivara study claiming it debunked Harborview, but that is not the case at all. It showed that helmets worked in the real world town of Seattle. It also showed that some impacts higher than those that can be handled by a helmet make the helmet less useful those greater impact energies. We know that, but it doesn't debunk anything in terms of what helmets can do and when they are actually effective, yes, in the real world where the forces may involve the same forces seen in the lab, though the lab numbers cover a much greater range of impacts than will be seen by any small survey. If anything, the conclusion should be that we should be calling for higher standards of protection than current offerings with CPSC approval. We can do that by buying to Snell levels, and the goodness of Snell is that they can push for more if the market is behind it. There's too many riders that don't care or don't know the difference right now.

The Rivara paper had some boneheaded ideas about what should be mandated based on findings, but that was like reading a tobacco company statement at that point as the author tried to turn it into a silly political point about gov't mandates. It's kind of funny because the assessment that it debunked everything else was similar to the idea that just because it found limitations of bath water that it somehow had a made the point that the baby should be thrown out too because that's what we were after in the first place.

COST 327 may also be useful. Yes, it's of motorcyclist accidents and helmets, but in terms of the types of forces, injuries, levels, etc it may hit on some of those that are relevant for bicyclists: https://ec.europa.eu/transport/roadsa...nal_report.pdf

That study was used in some of the critique of higher impact energy use in motorcycling helmets, though it showed much the same as previous studies, iirc.

mconlonx

Thank you for your astute correction. I will amend my statement: dueling desultory biased interpretations and intentional misrepresentation of studies and abstracts. How's that?

Increased helmet use does not result in reduction in serious injury to cyclists because helmets are not designed to mitigate serious injury. Helmets do work as intended, but work within parameters which differ in reality from what some users and most non-users perceive. Recent studies posted in this thread documented a drop in less than serious head injuries among helmet users compared to non-helmet users, which should be expected as that is the type of injury helmets are expected to help with.

RazrSkutr

Really? The Snell Memorial Foundation appears to disagree with you:

https://www.smf.org/standards/b/b90astd

I'm not sure where you think the kinetic energy of the mass of the head having a force applied to it is going? Helmets work by dissipating energy in the crushing of EPS. The result of that is that peak linear acceleration is reduced and hopefully the brain does not bounce off the inside of the skull.

You might find the following interesting, especially pg. 823
https://www.ircobi.org/downloads/irc12/pdf_files/86.pdf

License2Ill

The helmet manages the impact energy, it doesn't absorb it. It provides a controlled braking force, changes the rate of the application of the force. It's just a brake, not magic dust. The head accelerates, the helmet slows the acceleration event by spreading the energy out over time. The energy is not in the foam after it crushes. Have Ed Becker of Snell explain it to you if you want.

RazrSkutr

That's right... it's not to do with magic dust. The helmet does not, I repeat, does NOT function by crushing and absorbing energy. What actually happens is that the energy is converted into magic smoke which blows away in the wind. The transfer of kinetic energy into the work of crushing the EPS is NOT what is happening... that's just a lie. Carry on please.

License2Ill

You can see the smoke if you look closely. It makes no difference, but if you're looking for a helmet to absorb energy rather than slow acceleration through providing a braking force, you'll end up without a proper understanding of how they actually work and what they actually do. Then you'll be confused about the use g-force as the measurement for the injuries, and the fact that the head is providing the energy. Then you can blame the helmet for not absorbing energy as the source of your confusion. It doesn't absorb energy, it just slows the rate of transmission.

RazrSkutr

You'll forgive me if I prefer my own understanding of g-forces over that of someone that believes that it's possible to "slow acceleration" of an impact or "provide a braking force" without absorbing the energy of an impact.

You seem to be hung up on your inaccurate description, and ignoring the fact that we both agree that what a helmet does in ideal circumstances is to reduce the linear acceleration.

The only non-pedantic, interesting bone of contention is whether helmets of the current design are capable of dealing with anything other than a relatively narrow range of impacts... those within small range of those potentially occurring when falling off a bicycle and (as you claimed earlier.. suffering severe head injury and death as a result). There is a good deal of evidence to suggest that they don't.. both from materials testing engineers (see previous link) and from population-level data.

License2Ill

Every single study concludes that helmets prevent deaths and injuries in cycling accidents. To say otherwise is a foolish misunderstanding just the same.

You don't understand how brakes on your bike work either, do you? Like I said, it doesn't really matter, but when you get into the details about how helmets work it becomes important in understanding limitations and talking the same language to have a clear comprehension that a brake doesn't absorb energy and that the energy created by the head falling is not actually absorbed by anything.

License2Ill

Here's what Rivara actually said in summary:

The review found that wearing a helmet reduced the risk of head or brain injury by approximately two-thirds or more, regardless of whether the crash involved a motor vehicle. Injuries to the mid and upper face were also markedly reduced, although helmets did not prevent lower facial injuries.

https://www.thecochranelibrary.com/us...d/CD001855.pdf

LesterOfPuppets

Paper helmets, anyone?

https://www.bikerumor.com/2013/07/08/...er/#more-62696

License2Ill

I can't imagine those will pass any roll-off or strap retention test by the looks of pics. Either that or the CE standard is way too easy to pass. Is the EN1078 drop height only 1.5 meters for even the flat?

RazrSkutr

Wut? Does braking work by magic smoke too? The brakes and rims don't absorb the kinetic energy and turn it into heat? Please do tell me more... and do you have any interesting perpetual motion devices?

License2Ill

If the brakes were absorbing energy, they could return it back to my machine. Oh well, I guess I don't need them.