The first step in fitting bicycle helmets is to make sure you
buy the right one in the first place. Measure with the tape around
your head just above the ears and level front to back. Then select
the size as suggested in the table below. This is only your starting
point. The reality is that you have to go to the store and try
a bunch on, to find one that not only fits but is comfortable.
Then use the right number of foam pads that come with the bike
helmet to create a snug fit when it is placed level on your head.
The padding should exert enough force on your skin that if you
twist the helmet in any direction your skin should move as well.
Use the rear stabilizer mechanism, available on most helmets
to fine tune the fit around your head, not so tight though that
it cuts off the circulation to your brain.
the harness and the chin strap so that the helmet cannot be knocked
up away from the forehead and expose this area to a brain damaging
blow. If it does lift, loosen the clips that holds the straps
below your ears, shorten the front strap and retighten the clip.
You may now also have to adjust the fit of the chin buckle.
Try and pry the helmet forward over your eyes by lifting from
the back rim. If it moves enough to obscure your vision then shorten
the back strap that wraps around the back of your ear. When you
have readjusted both of these ear straps, there should be no slack
and the clip should rest just below the ear lobe.
The chin buckle should lay close to the throat and not around
the chin. It should be tight enough to allow for a firm fit, but
not so tight that you can't open your jaw fully as if you were
eating a Big Mac.
Readjust after riding with your bike helmet for awhile if you
find that the straps have stretched with use.
When all the straps, buckles and foam are adjusted correctly
you should not be able to twist the bike helmet more than 1" in
any one direction.
Bicycle Helmet Sizing Guide:
||Head size inches
||Head size cm
||20 - 21.75
||51 - 55
||22 - 22.75
||55 - 59
||23.25 - 24.5
||59 - 63
|One size - Men
||20.75 - 24
||54 - 61
|One Size - Womens
||19.75 - 22.5
||50 - 57
||18.5 - 20.5
||47 - 52
||20.5 - 22.5
||50 - 55
||22.5 - 23.75
||57 - 60
||19.25 - 22.5
||50 - 57
Mayo clinic report on the correct way to wear a bicycle helmet