HEAD CIRCUMFERENCE

(measured 1" above the ears)

Small = 19.25 - 20.5"

Medium = 20.5 - 22"

Large = 22 - 23.5"

NB : Measuring for helmets is not a precise art. The shape of your head is a factor, as well as the size. This means you may (for instance) be a Large for an ION 4D helmet but a Medium for the Air XP. There's no way to be sure without trying the helmets on. You may also need different size jaw pads to get a good fit (various sizes are available separately).

See if you can borrow someone else's helmet first to check the fit. Or, make an appointment to come and try all the helmets on at our fitting room. If all else fails, we have an excellent Returns Policy, but that will inevitably cause extra costs and delays so it's great if you can order the right size first time.