So you have just blown a considerable amount of dosh on buying that snazzy new gazillion bhp motorcycle and, like a responsible son/husband/friend/blah have also bought a good, matching helmet to go along with it. Great!
And so you are done with the running in and you come across an open road and suddenly the Rossi/Schwantz/Agostini/Doohan inside you pokes you on your shoulder and dares you to BE A MAN. "Awww come on, don't be such a sissy, mister."
And being the self respecting hot blooded man that you are, you wring open the throttle and your motorcycle starts to justify the many years of hard earned money that you have spent on purchasing it by going WAAAAAAAAAAA.....Your brain dumps a bucketload of dopamine in your bloodstream and you wring open the throttle further and further, firmly ensconsed in the belief that your snazzy lid shall take care of your cranium, even if your motorcycle goes KRAAATHUNNKKKK.
And then the KRAAATHUNKKKK moment arrives. You hit something/lose balance/something crashes with you, and your head strikes the ground with a massive THUNKKKKK. Your snazzy helmet rolls away and at the hospital, your doctor asks your near and dear ones "Head injury hai. Helmet nahin pehna tha kya isne?" (He has suffered a head injury; wasn't he wearing a helmet?)
The end. Finis. Sorry.
While most of us understand the importance of wearing a helmet, what we do not realize is that wearing an improper size of helmet could prove to be as disastrous in the event of a crash as wearing no helmet. No exaggerration, honest!
Crudely speaking, the best fit for your helmet is when it fits you like a balaclava - once strapped, the face should move with the helmet when the helmet is moved/pulled/pushed. Sounds uncomfortable till the helmet breaks in; but is true.
The first step towards purchasing a helmet is to determine the size of your head. It is a scientific fact that the broadest/widest part of a person's head is the area approximately 2.5cms/1 inch above his eyes. One should take a flexible inch tape and measure one's head at a few points both above and below this line to determine the greatest measurement of one's head. Most helmet manufacturers have a measurement chart (like we have for shoes, clothes, etc.) that would correspond to this figure. It goes like something this: Extra Small:
54-55 cms Small:
56-57 cms Medium:
58-59 cms Large:
60-61 cms Extra Large:
62-63 cms XX Large:
64-65 cms XXX Large:
66-67 cms XXXX Large:
68-69 cms XXXXX Large
: You must be joking
Irrespective of these sizes, one would do well to try out a helmet that is one size smaller/larger than his size in order to arrive at a snug fit.
Here's a youtube clip on how to correctly measure the size of your head when buying a helmet:
Take car or ride safe (read that again