Review: Giro Aeon helmet. Cool and cooler.

Giro Aeon. Hyper light, hyper vented.

Your initial reaction is shock

The new Giro Aeon helmet in a medium weighs a mere 222 grams — in fact, the European version goes all the way down to 189 grams. This creates a new term in your vocabulary: shocking light.

That’s where the story begins. To force that kind of weight loss, nearly every piece and part of the helmet went under the knife. First off, the internal roll cage frame is a polycarbonate material — it’s twice as light as the carbon fiber cage used in Giro’s high-end Ionos.

Aeon backside.

A quick inspection shows that the webbing is thinner, the side struts trimmed back to the essentials. The latest Roc Loc 5 retention system is 20% lighter than the previous version, according to Giro designers.

In addition, the structural ribs taper down in width as they reach your head. That CAD work took even more weight off and boosted ventilation — more on that headline shortly. You notice the disappearing grams instantly — everyone who picks up the Aeon has the identical OMG moment.

Roc Loc five. Dialed-in.

Low weight meets high style

Almost from day one, Giro has set the high bar for design and visual style  – they are the Oakley of helmets. In Bicycling Magazine’s Gear Hall of Fame, the original 1985 Giro Prolight ranks #2. The Aeon shows off the company’s endless flair for creating head-turning head gear. There are nine color combinations from understated mattes to optic yellow.

From any angle, it’s hyper-sculpted, aggressive and beautiful — a high speed exoskeleton built for racing fast. The design language is distinctive: a style that’s H.R Giger crossed with the cyber-esthetic of William Gibson. It’s what Schwarzenegger’s Terminator might wear if the android was riding the Tour de France. In other words, yes, the helmet looks pretty darn cool.

Rock Loc 5 rocks

The latest iteration of Roc Loc is a step forward in structural integrity and fit. There’a reassuring and firm click to each turn of the ratchet dial.

The old system worked just fine but lacked the ability to adjust with one hand. Now you can make an adjustment on the bike, just reaching back to redial. The struts are also extra flexible in the Aeon so they conform more easily to the unique shape of your noggin. Height adjustment is generous — 15mm up or down.

Aeon insides.

Vents re-invented

On weight and style alone, the Aeon is a tempting package. But light weight and singular beauty miss the biggest story of the Aeon: the ventilation is superior.

Thanks to those tapered ribs inside, the part of the helmet that actually rests on your head is fairly minimal. What that means is that in-coming air now directly cools a larger area of your head. Remember, it’s not just the size of the vent opening but how much of your head the air reaches. The Aeon is the air cooling king.

On the Road

We searched dilgently for a small flaw in the Aeon and really, we’d have to invent one. (Drawback: too good-looking!) The interesting thing we noticed is how the helmet seemed to rest so lightly. We suspect that’s not just grams lost — its a side effect of the exceptional venting. The Aeon rides firm yet the sensation is that it almost floats. That is cooling and very cool at the same time.

The Aeon is the definfition of Giro: an elevated level of design, terrific venting and gram-slashing lightness. We pity their designers because they’ve raised the bar so high that going any higher will be quite a challenge.

Giro Aeon $250