A regular cycling regimen leads to health benefits ranging from a bolstered cardiovascular system to an overall increase in life expectancy. But while biking is a low-risk activity compared to activities like football, basketball or snow sports, a helmet is key to your safety. Giro's Ionos and Atmos helmets both fit the bill for road bikers, but they differ in the details.
Giro recommends both the Ionos and the Atmos helmets for casual road cyclists, road racers, commuters, touring bicyclists and triathlon competitors. Each helmet features an in-mold composite sub-frame under a polycarbonate shell. Likewise, both models focus on ventilation, utilizing Giro's Wind Tunnel ventilation system, which combines external vents with internal exhaust channels, encouraging an in-and-out cycling of air. The Ionos and Atmos both use the Roc Loc 5 fit system. With this system, a dial on the helmet allows you to adjust its tension and vertical position on the fly. If style gets you going, Giro offers both helmets in a wide variety of hues, from black-on-black to lime green with white trim.
Only on Ionos
Unlike the Atmos helmet, the Ionos features X-Static padding, a machine-washable cushioning with antimicrobal properties. In contrast, the Atmos has a regular foam liner. The successor to the Atmos model, the Ionos is very similar in appearance, but it sports a slightly longer, slimmer form factor than its cousin, with somewhat more distinct points near the helmet's crown. The professional reviewers at BikeRadar give the Ionos mostly positive marks, citing the helmet's cooling capabilities and fit, but noting that these features come with a high price tag.
To bolster safety for road cyclists, the Atmos features an in-mold roll cage, made from a web of nylon inside the helmet's foam liner. Although both helmets rely on Giro's Wind Tunnel design and both feature internal channeling, the Atmos edges out the Ionos with 26 individual vents compared to the Ionos' 21 vents. In their review, Road.cc praises the lightweight, plentiful ventilation and snug fit of the Atmos, but mentions that this model comes at a hefty price, like the Ionos.
Budgeting for Safety
At the time of its release, the Giro Ionos was substantially more expensive than the Atmos. In 2013, Giro stopped manufacturing the Ionos helmet. When purchased new from the manufacturer, Giro offers a one-year warranty for product repair or replacement -- by making a used purchase, you also lose this option.