 For Gentex Helmets Measure your head circumference as shown and place that number in section requested when ordering your helmet. You can use metric or American standard.

ALPHA HELMETS
 When measuring your head for an Alpha Helmet, measure side to side first, then front to back and use the circumference measurement last. If you fall between two helmet sizes, choose the larger helmet.
Circumference Head
Width
Head Length
Size
21 1/2 - 22 3/4"
5 1/2 - 6 1/2"
7" - 8"
Medium
22 3/4 - 24"
5 3/4 - 6 1/2"
7 3/4 - 8 1/2" Medium Long
22
3/4 - 24"
6 1/4 - 6 3/4"
7" - 8"
Medium Broad
23 1/4 - 24 1/2"
6 3/8 - 6 3/4"
7 3/4 - 8 1/2" Large
24
1/4 - 25"
6 3/4 - 7 1/8"
8 1/2 - 8 3/4" Extra Large |