The correct fit of the helmet is critical to its performance during an impact. For maximum protection, the helmet must fit correctly with the securely fastened chin strap and provide adequate peripheral vision.
Measuring the head is only the starting point for the entire sizing process. Due to the different shapes, a head that is obviously the same size when measured with a tape measure may not always fit the same size helmet.
Initial measurements can be taken using a small metal tape measure or cloth tape. You can also use a string and place the string on the tape measure.
The circumference of the head should be measured approximately one inch above the front of the eyebrows and the maximum possible measurement at the back of the head. Take several measurements. The largest measurement is the one you want to try first. If you are using a balaclava or headgear, be sure to measure and wear the headgear properly. Use the Bell size chart to determine the size that best matches your head size.
SIZE COMPARISON CHART
Full Sizing Table
When worn correctly, the helmet should be worn low on the eyebrows, with the eyes close to the center of the eye opening, touching the top of the head, with even and firm pressure all around - tight and without excessive pressure points.