Giro 2007 Xen helmet

Pictures: White/acid green , Matte black

The Xen is Giro’s best open face MTB helmet. It combines the smooth styling of skate helmets with the light weight and high ventilation of top end XC helmets. It has 17 wind tunnel tested vents to make sure air cooling happens even at slow speeds. It weighs 11 oz. and comes in three sizes to fit comfortably on almost all adults.

The Xen uses Giro’s Roc Loc 4 fit system, which is adjustable in both tension and position. The Roc Loc 4 makes for a truly custom fit and is ponytail compatible. The chin strap is held in place with cam-lock levers, which pop open for easy adjustment, then snap back closed and don’t slip. The visor provides shade and can be removed if you don’t want it.

All Giro helmets are CPSC certified, which means they pass the industry standard tests for safety. Giro uses “In-Mold” Microshell construction for almost all their helmets, a process that permanently bonds the EPS foam layer to the hard outer shell. This makes Giro helmets much stronger and more durable than other helmets where the outer shell and EPS are just taped together.

The Xen comes in three sizes, fitting heads ranging from 20” (51cm) around up to 24.75” (63cm). If your head is bigger than that, look at helmets made specifically for large heads—the Giro Atlas II fits up to 25” (64cm), and the Bell Triton fits up to 25.5” (65cm). For heads at the bottom of the Xen’s size range, you can also consider the Giro Skyla and Flume helmets, which fit heads down to 19.75” (50cm) around.

The Bell Sports company owns the Giro brand, and Bell Sports makes both Giro and Bell helmets. Bell and Giro helmets share many features, but one thing they don’t share is shape. Giro helmets use a slightly oval mold (longer front to back, narrower side to side), while Bell helmets use a more round mold. If your head is large and more oval shaped, a Giro helmet might fit better. If your head is large and more round, a Bell helmet will probably fit better. If your head is of average size, you probably won’t notice a difference and will get a good fit from either brand. In that case pick a helmet based on the features or design or colors you like and don’t worry about the brand—both Giro and Bell are excellent helmets.