To determine the proper fit of your helmet, measure your head size by passing a tape measure around your head approximately 2 cm above the eyebrow line. Use the largest measurement from this process. Select the helmet size that matches closest to the measurement. Since the helmet sizes do not always match perfectly with basic measurements, use the helmet size that fits snugly, but without pressure points.
To check the proper fitting, place helmet on your head. Make sure the helmet lining fits snugly around your head and that the cheek pads are pressed close onto your cheeks. There should be no space between your brow and the lining. Take hold of the helmet on each side and try to move the helmet up and down as well as side to side. You should feel the skin on your face and head being pulled along with the helmet. If the helmet is able to move freely without rubbing your skin, the helmet is too large and you need a smaller size.