GMAX Helmet Size Chart
Your helmet is the most important part of your riding gear.
Make sure it fits correctly.
A properly fitted helmet will improve many aspects of your ride. It will make you more comfortable by not creating hot spots. It will make you more aware of your surroundings by dampening noise and increasing visual clarity. In the event of an accident, a helmet that fits your head properly will have the best chance of protecting you from injury. The helmet fitting methods described here are focused on fitting for full face helmets. Many of these same techniques will apply to 3/4 and half-helmets as well.
1. Size Chart
To find your approximate size measure the circumference of your head one-inch above eyebrows and across the largest portion of the back of your head. Cross reference this measurement on the helmet size chart to determine the approximate size.