HJC CS-R1 Owner's Manual page 7

:Selecting the Right Helmet
6. Test the helmet fit by placing your hands on each side of the helmet.
While holding your head as motionless as possible, try rotating your
helmet from left to right then up and down. If you can feel the helmet
padding sliding on your head, it is too big, try a size smaller.
You should feel the helmet move the skin on your head and face as
you try to move the helmet.
7. Fasten the retention system (chin strap) as tight as possible under your jaw without causing
pain. There must be no slack in the strap, and the strap must be tight up against your jaw. See page 11.
8. Test the retention system (chin strap)
• Put your hands on the back of the helmet and try to push the helmet
off by rotating it forward.
• Put your hands on the front of the helmet above your forehead
(or on the chin guard) and try to push the helmet off by
rotating backward.
~AWARNING If helmet comes off, try another size or another model or brand.
Repeat steps 3 through 8 until you find a helmet that fits your head snugly and securely. 6