When considering the purchase of a new helmet it's good to remember that one of the most delicate, yet often underappreciated, steps is choosing the size. While it is true that too tight a helmet feels unbearable, it is equally true that one which is too large won't fulfill its protective function. Helmets offer maximum protection only when the size is right.
It is important, then, to not merely guess the size, but to accurately measure the head and refer to the size chart provided by the manufacturer. Something else that needs to be considered is that heads have different shapes even when the circumference is the same. This is why it is essential to try a helmet on before buying it.
Five quick steps to make sure that the size of your helmet is correct
1. Put the helmet on and fasten it, making sure that the strap is not loose but not too tight; it must be close-fitting, without being uncomfortable.
2. When the helmet is on, there should not be any gap between head and padding. If there are any gaps, above the crown of your head for example, it means that the helmet is too small. The helmet must be snug around the entire head.
3. At the same time, you should not feel any pressure points, especially in the front area and on the nape of the neck. It is best to keep the helmet on for some minutes to make sure that there are no uncomfortable contact points.
4. Try tilting the helmet sideways and up and down. With a full-face helmet of the right size, the cheeks will remain in contact with the cheek pads when following their movement. If the helmet moves too much or even turns on the head, the size is wrong. 5. The last test is retention. With the helmet fastened on, tilt your head slightly forward and apply light pressure at its rear bottom edge. The helmet must not slide forward.