Bicycle Safety Helmets On Display

Part 2: Technology For Bicycle Helmet Safety

I need a new bicycle helmet, and my wife says "Buy whatever protects you best".  That's a nice sentiment, but how do I choose?  This is Part 2 in the Quest for the "Safest" Bicycle Helmet.  In the process, we're learning a bunch about Bicycle Helmet Safety.

In Part 1, we found there are a lot of interesting technologies, and we also quickly discovered that helmet manufacturers are not keen to give actual data about the safety of their helmets.  That leaves us, the customer, deliberately out in the dark as we strive to select a "Safe" bicycle helmet.  Though hiding data is wrong on several levels, we'll do what we can with the information available.

Engineering Evaluation

Admittedly, the task of evaluating relative bicycle helmet safety without the help of testing machines and scientific data is a tall order.  Of course, we can't possibly end up with a true and complete picture, but since a relative perspective is the criteria for this search, we'll give it our best shot.  Please note, the information in this and the previous article is opinion, based on engineering judgement.  The opinions are from understanding, from research and engineering evaluation, but we are not bicycle helmet experts.

The internet is full of opinion, extrapolation and biased reviews, so the First Step is to sort and separate the advertising from the honest.  As noted in Part 1, that's a bit of a chore, but in the end, it leads to the people who really are the experts.

Second Step is to carefully consider the technologies and factors that affect bicycle helmet safety.  Then, use engineering experience and knowledge to analyze and decipher the propaganda.  (In a portion of the bicycle industry scared to show their cards, propaganda and sales pitch are all they will give us.)

Third, before coming to conclusions, it's time to talk with some "experts" and hear their take.

That's the process for this article, and the opinions formed are below.

Engineering Observations Of The Technologies

First, MIPS

MIPS Bicycle Helmet Safety LinerLet's talk about this MIPS thing with all the buzz.  I found it interesting that sales folks mostly support MIPS, but only a few are solid on recommending it.  On the other hand, most "experts" are skeptical about the extent to which MIPS will help in a crash.  Not many experts (I found) fully endorse it, rather they say something like "It probably won't hurt anything".

After all the reading and conversations, my take is that it can likely help in the right kind of crash, but could easily hurt more in other types.  I say that mostly because of the implementation of the idea, rather than the idea itself.

So, the concept is that the helmet can move rotationally a little different than the head.  That I agree can be a good thing based on the studies cited.  However, when you consider the most dangerous things about helmets - it's the things that stick out, the things that can snag other objects in a crash.  These include Go-Pro mounts, or helmet mounted lights, or kids helmets with horns or ears off the sides, etc..  In a crash, these things can catch something (like a rock or crack in the pavement) and twist your head much more severely.  The idea with MIPS is to improve bicycle helmet safety by allowing some helmet twist independent of the head.  Sounds good, right?

What Those Close To The Company Are Saying:

MIPS Helmet ConnectorI don't know the exact role of the person who said this is, but it's published as an answer to a great comment in an article about MIPS.

First the insightful comment:  I don't like statistics without context.  What is a "50% better helmet?"  And "eliminate" kinetic energy? Come on.  Not even an F1 helmet can eliminate energy.

Then the Answer:  I did pursue the question of the efficacy of the design in the field, but it's a very difficult issue to test, since there are far too many variables associated with any accident/collision/fall.  So while the results from lab testing are clear, MIPS does not make any specific claims for what that means for the individual taking a tumble and hitting their head.

Is this a recant of the reason for MIPS in the first place?  From what little I've seen (including white papers from MIPS about MIPS), the lab tests are far from simulations of real falls, so I'm quite skeptical of the results.

Furthermore, they won't publish test data.  Where's the proof?  Can we not take one or ten of the thousands of videos of crashes and simulate them in a test to really demonstrate what is or is not?  Show us, and quit making up stories!

Implementation Is The Issue
MIPS Helmet Tag

MIPS Helmet Tag - The graphic shows one thing, but the disclaimer denies it. They are implying they have brain scans during a crash, which is obviously hog-wash, so the graphic is a blatant lie.  Their tech papers even say they can't prove it works.  This kind of misleading marketing scares me.

The current implementation of MIPS allows the helmet to rotate freely (up to the point that your head jams sideways in the helmet and suddenly stops rotating independently and takes your head with it).  It effectively exposes more surface of the helmet to the ground if it rotates as designed.  This means there is more chance of catching something sticking out - which can even be the edge of the helmet itself.

With this in mind, speaking only about the current implementation of MIPS (with the little rubber band connectors), it's my opinion that it's a great idea, but implemented in a way that increases exposure, and could very well do more harm than good.  At first introduction I was excited.  However, after listening to several experts who leave questions, and thinking on it much more, I'm not sold.

From what I've seen so far, MIPS has a ton of marketing behind it.  Why?  Because it costs very little to implement, it has a good story about safety (even if it's exaggerated).  Oh, and it's new, so it's something to talk about in a relatively stagnant industry.  It's very important to note that there's no data to the story - even by MIPS own account.  It's the perfect smoke and mirrors.   To me it seems like a way to up-sell customers by getting them to buy a more expensive bicycle helmet.  Or, to pay $20 more for the "improved" version of the helmet they were going to buy anyway.

The Alternative To MIPS

The obvious inexpensive (and maybe better) alternative to MIPS is a helmet with smooth exterior surfaces, and the absence of anything poking out.  That will reduce the torsional input in a crash by sliding rather than rotating, thus helping bicycle helmet safety.  Hmmm.  I guess I'll have to re-think mounting my light.

There are some other technology alternatives too, like Omni-Directional Suspension (see below) and others.  I'll leave that to your own research.

More on MIPS and a recommendation for better implementation is contained in the Wrap-Up Post.

Second, Koroyd

Koroyd Bicycle Helmet SafetyBicycle helmets with Koroyd have a unique look with the soda straws all glued together just under the outer surface.  OK, it's not really soda straws, but rather a honeycomb of thin plastic tubes reminiscent of soda straws.  This technology also has it's share of both skeptics and staunch supporters.  Truly, this is where grading the tests would seriously help in the discussion (see Part 1) - but I digress.

In a crash, the Koroyd crumples as a way of dispersing and distributing energy to extend the time of the impact.  It's a lot like the idea of crumple zones in cars t0 protect the occupants.  It's certainly a different way of doing it.

From an engineering perspective, this offers some really interesting advantages.  First, the Koroyd covers the entire head (at least some of the helmets).  Second, crush zones with lots of small collapsing elements is proven to work very well in impact.  (I'd love to see the real numbers for this helmet with respect to EPS.)  Third, it's pretty light.

Extrapolating here, it appears that in a minor accident, only areas under the outer shell (not in the vents) would be involved in supporting the impact.  In a more serious hit, the Koroyd in the vents would also crush giving more complete protection.  Does that mean Koroyd in the vents provide a gradient of loading for more protection in a serious crash?  How about multi impact protection?  I don't know.

Koroyd Disadvantages

Smith Bicycle HelmetThe first obvious disadvantage is airflow blockage.  In the Smith Helmets there are several "vents" from the outside, but because of the Koroyd tubes, airflow is not as good as if the vents are full open.  Owners of this helmet say it is warmer, but only a little, and not noticeable except on hot days.

A second disadvantage is the reaction member for impact absorption is your head.  That means your head gets the edges of the Koroyd straws in a crash, which can't feel very good.  However, this seems a small inconvenience for the added safety if you do have a serious accident.

The third disadvantage (which may actually be an advantage) is damage to the straws, if any, will be readily apparent, and the helmet won't fit as well after.  With the older standby, EPS foam, it's hard to see actual crushing of the foam areas when it's not severe.  I have not seen a crashed Koroyd bicycle helmet, but I understand the distress is pretty obvious.  (If you have such a helmet with the unfortunate experience of crashing hard in it, please send a photo of the damage and a short story about the experience.)

In My Opinion

Koroyd is a technology that peaks my interest.  It appears that this is a legitimate attempt at a better / safer approach.  I think there is a lot more to this technology than first meets the eye.  Smith hints at it some, but I think they're holding back when it comes to the real story.  Smith?

Third, Multi-Density Foam

I won't spend a lot of time on this because there isn't much data.  The concept is to use multiple (usually 2) different densities or types of Expanded Polystyrene (EPS) foam to offer a broader level of protection.  The lighter foam responds better to lighter impacts, and the more dense foam responds best to the heavier impacts and provides a better spread of energy.  The cool parts of this technology come with the shaping of the foam within the helmet.

Engineering wise, this looks like a wonderful improvement for bicycle helmet safety.  The catch - it requires a little more space.

From a business standpoint, this technology seems like it could really shine if the legal CYA constraints were lifted.  I can see this technology doing much better on tests when optimized to see just how well it can perform.  For now, it's interesting, but unless there is a driver to really do something, it likely won't go as far as it could.  That statement makes me sad.

(As a side note, the best implementation for dual density foam that I've seen is in Kali Helmets where the one density is cone shaped and intermingled into the other density.  Conehead.  That looks great to me because it spreads the load and offers a variable rate crush.  But, I diverge.)

Fourth, Omni-Directional Suspension

Omni Directional Suspension IllustrationOK, this technology really gets me going.  I hope I'm not a sucker for the great presentation on their website or for the propaganda about how it works.  Well, whatever.  I bought one to see, and so far I'm liking it.  (Though I hope I never get to really test it.)

Impact Test DataThe advantages claimed by the manufacturer, 6D, are multi-level impact absorption and minor, (but important) rotational movement in a crash.  And, they show (foggy) test data to back their claims.  To me, their material speaks directly to Bicycle Helmet Safety and what they are doing to improve it.  It has 2 EPS foam shells with different densities (see Multi-Density Foam above) suspended by a shock absorbing system that incorporates stable rotational freedom.  Read their website for details.

Also, the helmet extends down the back somewhat for greater coverage, and the sides are pretty smooth - supporting another of the recommendations above.

Does it work?  Well, I hope I never find out, but examination of the helmet sure shows that it should.  You can move the inner shell slightly independent of the outer one.  It's like MIPS with a lot more control.  Certainly 6D has implemented a much more stable way (and in my opinion, a safer way) of accomplishing the task.

6D Disadvantages

Of course, there are always trade-offs.  The two disadvantages from a safety standpoint that I see are Size & Weight.  It's a little heavier, and it's a little bigger than my previous lids, but not drastically.  I mention it here in the discussion about safety because both Size and Weight are counter to safety.

OK, think about this a little.  A larger volume helmet can absorb more energy and slow down the impact more than a smaller volume one.  That's really good.  In this way bigger is better.  On the other hand, a larger helmet gives a longer effective lever for the ground to wrench your head around should you come in contact.  So, size is a plus and a minus.  To put this in perspective, however, the added size makes a relatively big difference for impact protection, and only a small minus with respect to being a lever.

Weight, on the other hand does not have much benefit.  It simply means your head has an increased mass that must stop or change directions quickly in an accident.  Anything that makes your head whip around more is a bad thing.  The weight of the 6D bicycle helmet is 517 grams.  The Giro I'm replacing is 325 grams.  So, almost 60% (192 grams) is huge.   Compare the Smith with Koroyd at 315 grams.  The 6D is noticeably heavier, and that's worth thinking about.

Functionally, the 6D can be a little warmer than others because it does not have as many vent holes.  It's a trade-off for more coverage and safety, with a few less vents.  Also, this helmet is on the higher end of cost.  This is one that seems to reflect getting more safety for more money.  But, I have no independent data to back that up.

Other Technologies Involved In Bicycle Helmet Safety

It is not discussed in literature I saw, and most of the people I spoke with didn't give it too much mind for bicycle helmet safety, but the head grabbing straps inside the helmet key some attention for me.  There appear to be 2 general ways to attach bicycle helmet straps to the shell of the helmet.  Photos below illustrate the two approaches.

Attachment of Bicycle Helmet Safety Straps
2 Methods of attaching the chin straps - Direct to Edge of the Shell (Left), or Connected to Inner Body of the Shell (Right).  From a safety standpoint, is one method better than the other?

What do you think?  From a bicycle helmet safety standpoint, is it better to have the straps closely contact your head?  Or is it better to have the straps connecting to the outer edges of the helmet?  Both ways connect straps to the outer shell of the helmet.  One method does it wrapping into the helmet, and one method connects via terminated ends at the helmet edge.

The object of the straps is to hold the helmet in place.  They need to hold the helmet where it belongs during impact and during any scraping that may occur.  It is very common to have multiple impacts during one crash, so the straps are responsible to keep the helmet in place on your head during all of it.

I don't have an answer.  And maybe it's just a comfort thing more than a bicycle helmet safety thing.  If it is about safety, I'd guess straps that fit closer control the helmet better?  However, I have not studied crashes enough to know.  As mentioned above, this strikes me as a pretty important aspect of bicycle helmet safety, but it's not talked about.  So, if you have knowledge on this topic, please let us know.

Bicycle Helmet Safety - Conclusions

Back to our Quest:  What is the "Safest" Bicycle Helmet?  I'm not sure, and I have only begun to scratch the surface of what's out there.  I also have not spoken to all the experts, but I feel like the leading technologies are Koroyd and Omni-Directional Suspension.  Everything I found uses EPS foam in portions of the product (even with Koroyd), so it's obviously the favorite.  It may be older technology overall, but in terms of bicycle helmet safety, it has proven itself over and over in protection.

Helmet Chosen For Safety

The 6D helmet I purchased. Since then, they have improved the system even more for better safety.

The most important conclusion from this study is not in the helmets themselves - it's in the culture.  If we really want to improve bicycle helmet safety, we must find a way past the legal CYA.  Right now, that issue alone shields the industry from itself and from good customer decisions.

Make test results available, then let customers choose helmets based on complete information.  Let the market dictate how safe is "safe enough" rather than by some ancient pass/fail test.  There will still be riders that choose sleek and stylish over greater safety, but it's a choice they can make.  Right now, there is NO CHOICE for those customers that want more impact protection than regulated by a pass/fail;  That is for customers more concerned for safety than looks.  The helmet industry should be ashamed of that.

The Quest:  What is the Safest Bicycle Helmet?

OK, we can't just leave The Quest unanswered.  We started this by looking for a replacement helmet, so where did we get?  While I am not certain it's the "Safest", I chose the 6D Trail for it's attention to the many aspects of safety.  6D is the only company that outwardly addresses the many aspects of potential crashes (low speed, high speed, rotational).  For that alone, I'm willing to support the company.

As a last thought, 6D gives an attempt to back their claims with something that looks like data even if they don't complete the picture.  I'm pretty sure they are also caught in the legal CYA, but they are at least trying.  I give props for that.

Runner up (and I'll probably buy one for CX and Road) is the Smith Overtake - without MIPS.

Follow-Up

The Wrap Up for this study on Bicycle Helmet Safety came after Interbike.  Read it here.  Your comments are welcome.

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