Nov 24, 2007

Motorcycle Helmets: What does the outer shell do?

If you have read the above, you already know. The basic job of the outer hard shell is five fold. First, it needs to absorb and spread any sharp impacts over a larger area to reduce the peak impact strength. As in, the same force, spread over a larger area will hurt less (or, to paraphrase, have less destructive energy). Second, it needs to offer excellent abrasion resistance so that the EPS liner inside does not come into contact with the road and wear away. Third, it needs to offer very little resistance to sliding along the road. If the helmet happens to resist sliding along, it can put unnatural forces on the neck area adding to the injuries. Fourth, it needs to protect the EPS liner from minor knocks that helmets tend to suffer in daily use. You know the ones I mean, the accidental brush with the elevator door, the careless put down when the lid nearly rolled all the way over etc. Fifth, finally, the helmet, being the highest point of a motorcycle-rider combination also needs to attract attention (getting noticed is a crucial component of safety in traffic) and look good (you'd rather look good, than shabby, right?).

Related links in this series:

Other links on helmets

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