HOW DO I KNOW IF MY HELMET FITS CORRECTLY?
CAN I REPLACE JUST THE LINER IN MY HELMET?
Yes and no. There are two types of helmets.
A single impact helmet usually carries a safety rating, and is often used for bicycling. The helmet “complies with U.S. CPSC Safety Standard for Bicycle Helmets for Persons Age 5 and Older”. This type of helmet has a hard foam liner inside the colored plastic “shell”, and a thin lining of soft foam inside that. These helmets are meant to protect your head at high speeds (such as bicycling). If they take a hard impact, that hard foam is meant to crack, and the helmet has done its job and should be disposed of.
A multiple impact helmet (most common in derby) has a soft foam liner that is thicker, and no hard foam between it and the shell. It is not meant to protect the wearer from high speed impacts, nor does it carry a safety rating.
The shells of each brand of helmet are the same size, it is only the liner that is different. So a person with a small helmet has the same size shell as a person with a large size helmet. The liner is thicker in the small helmet than in the large.
DO I NEED TO REPLACE MY MULTIPLE IMPACT HELMET AFTER A BAD FALL?
Sometimes. If you get a level 2 or above concussion, why take the chance on there being damage to the foam or shell that you cannot see? As a general rule, no, but you do only get the ONE brain, so…