I thought I'd share some of the info I gleaned from many hours of research into the subject. I have summarised the main findings here and I have included links to most of the source documents I used to gather this info at the end of the post. Sorry if it's a long one...
I'm sure that like me, you want to have a comfortable helmet and a stylish one to boot. But what about safety? All helmets are certified to a certain standard before you are allowed to use them on the road, right? But there are some marked differences between these safety standards and what will pass the test.
The first article I read on the subject was from motorcyclist magazine:
http://www.motorcyclistonline.com/ge...helmet_review/
(as a quick note, please don't just shoot off here. Read this post, then click on to each link below to see what I'm talking about. If you decide to read it first, please come back - for your head's sake)
This was the one that really got me thinking and started my research journey that would last all the way through when I should have been doing other things, but justifiable as it turns out.
I'm glad I didn't stop reading there. While there were some findings in that report that got me thinking, as is always the case - no one article should provide all the information you rely on for such an important purchase.
There's more to helmet design than peak G transmission alone and whilst thorough, MC mag didn't report on these other considerations.
I found a number of articles across the web, some research papers, etc… (see ATSB website of Australia for a couple, links at the end of post) What I have found is that many researchers comment that the upper levels of the Snell, EC and AS1698 certifications of 300, 275 and 300g respectively are too high and should be revised downward to about 250g. Bear in mind that most of the bigger brands (Arai and Shoei for example, who set their own limits at 200g and 150g respectively) - perform well below the limits and the lower recommendations.
It seems that fiberglass helmets may transmit higher g loadings than polycarbonate shells, but this is not the full story. Brain stem damage and BSF (Basilla Skull Fractures) (both often fatal) from frontal accidents (which represent about half of all head collissions surveyed) are better offset by stiffer fiberglass shell helmets. Frontal collision testing is only required by the EC and Snell certifications. Furthermore, fiberglass helmets offer lower sliding resistance and thus transmit lower rotational forces to the head and neck. There were mentions made to the extra weight of fiberglass helmets negating some of this sliding benefit but most of the newer composites do not have a significant weight disadvantage over the abs and polycarbonate ones.
So for the trade off of what may seem like a significantly higher number of peak G's transmitted for 5ms - but still well below certification requirements and even recommendations, is more than made up by the fact that these stiffer helmets are more capable of saving your life by significantly reducing your exposure to BSF and brain stem damage caused by jaw compression into the brain stem area.
Note - you NEED your brain stem to live, higher level cortical functions can sometimes be taken over by other parts of the brain if a diffuse brain injury is suffered, or you can still lead quite a satisfactory life without some. That said, I'd prefer to have all of them.
As is always the case, there is never one article that says the whole story. As for me, I chose a composite fiberglass shell, snell (as well as DOT, AS1698 and EC 22.05) certified helmet. Not because of its snell certification alone, but because after weighing up the options set by the current required standards of certification I feel that it is the best protection available from these other types of injury that aren’t considered by the motorcyclist article, nor by the DOT and AS standards.
For the record, I got an Arai Vector. I tried on plenty of helmets, each for about half an hour or so (sometimes to the assistant's displeasure) to get the right one. I was pleased with the Arai approach to safety and the comfort was the best of all I tried. There are different shaped heads and helmets for those heads, take the time to find the right one. The only thing about it is a slight whistle at >100k's, only noticable when i have ear plugs in. That and the visor is a bastard to get back on after cleaning it.
I hope that my many hours of toil will make it that much easier for you to decide on your next helmet.
PS. Some of the articles I found mention the kind of nasty stuff you don't want to think about happening to you. If that upsets you, take my word for what was contained therein.
Acknowledgements and source documents:
http://www.atsb.gov.au/publications/...ort200703.aspx
http://www.atsb.gov.au/publications/...le_helm_1.aspx
http://www.atsb.gov.au/publications/...le_crash_1.pdf
http://www.carrsq.qut.edu.au/publications/
http://www.webbikeworld.com/motorcyc.../ece-22-05.htm
http://www.smf.org/articles/mcomp2.html
http://www.araihelmet-europe.com/
http://www.shoei-helmets.com/road/rd.aspx
Linear Mode
