Find your fit
Two minutes with a tape measure now, or a helmet that rocks on every descent for the next four years.
How to measure
Take a soft tape measure and run it around your head about a centimetre above your eyebrows and ears — the widest point. Keep it level front to back. Read the number in centimetres and match it below. If you land within 5mm of a boundary, take the larger size: the micro-dial takes up slack, it cannot create room. Exchanges are free in both directions for thirty days.
Three sizes
52–56 cm
245g. The smallest shell, not a padded-down medium — the shell itself is moulded smaller, so the proportions stay right.
56–59 cm
260g. The size roughly six in ten riders take, and the one every published figure on this site was measured on.
59–62 cm
278g. Same vent count and same channel geometry, scaled up — you do not lose airflow by having a larger head.
Between two sizes?
Order the larger one. If it is wrong we swap it and pay both ways.