Proper motorcycle helmet sizing is paramount for safety. A correctly sized helmet sits level on the head, with the front edge approximately one inch above the eyebrows. The cheek pads should make firm contact with the cheeks, and there should be no excessive movement when the helmet is grasped and rotated.
The effectiveness of a motorcycle helmet in mitigating head injuries during a crash is directly correlated to its fit. A helmet that is too large may shift or come off during impact, while a helmet that is too small may not provide adequate coverage. The development and adoption of standardized sizing charts by helmet manufacturers has significantly improved the accessibility of appropriately fitting head protection.