Regardless of a helmet's price point, features, or styling, it's essential to get a comfortable helmet that fits properly. The prettiest hand-painted Lance Armstrong replica helmet is useless if it doesn't do the one thing it's really designed to do keep a rider alive.
How It Works
The functioning of a helmet is extremely simple: A layer of foam surrounding the head spreads out the shock of any impacts while it also keeps the head from contacting objects that could cause trauma. The thin plastic layer on the outside of the helmet prevents scratches or damage to the foam layer and allows branches or other objects to bounce off the lid.
In order to conform to a wide range of heads, helmet manufacturers produce a vast array of sizes, modifiable even further by padding, straps, cinches, and ratchets. Typical sizing systems include extra small/small, small/medium, medium/large, and so on. (Children's sizing tends to run by age and is even more critical than adult sizing. A small head is a growing head and very important to protect.)
Most helmets come with extra padding strips that can be strategically placed inside the lining to make a helmet feel more comfortable. It's important to use only manufacturer-provided padding since non-approved materials can damage the helmet and the head.
A recent addition to many lines of helmet is a rear-retention system designed to create a tighter fit between helmet and head. Many cycling injuries are caused by an improperly fitted helmet; riders seem to prefer them slid too far back on the head. The retention systems (such as Giro's Roc-Loc and Bell's Half-Nelson) put a strap at the rear of the skull, above the neck, which places the helmet in the right place and keeps it there even during aggressive movement.
Details mentioned in this article were accurate at the time of publication