Giro Aeon helmet

The Giro Aeon is a brand new high-end racing helmet that's both lightweight and airy - the best of both worlds.

Previously, the Ionos (£169.99) was Giro's best-ventilated helmet although, at around 300g, it wasn't particularly light. And then there was the Prolight (£149.99) - just 175g, but less airy. Both of those helmets still exist in the range but now, straight in at number one, comes the Aeon.

Okay, the simplest thing first, our medium (55-59cm) model weighed in at 189g. There aren't too many helmets out there that are lighter than that. Is that important? If you're a performance rider and every gram counts, well, all those little savings add up. What's more significant, to my mind, is that a lighter helmet is just a touch more comfortable on your head. Not much, but a touch.

Interestingly, Giro give the US version of this helmet a claimed weight of 222g - and we find that Giro's weights are usually pretty accurate. That helmet conforms to American CPSC standards. This slightly lighter model conforms to European CE standards. It's a strange old world.

One of the advantages that the Aeon has over the Prolight is the fit system. The Prolight features Giro's Roc Loc SL system that doesn't offer a whole lot of adjustment. There's an elasticated band across the back of your head that provides the grip. The system works fine for me - I've been using a Prolight periodically for about a year and a half - but it doesn't feel quite as secure as some other designs, and some people really don't like it. If it doesn't fit, it doesn't fit; you can't alter it.

Like the Ionos, the Aeon comes with Roc Loc 5, Giro's top fit system, which you adjust via a little clicky wheel at the rear. Sorry, that should read, a 'ratcheting, micro-adjusting dial' at the rear. Either way, it's a one-handed job so you can easily alter the fit on the fly. You get a good amount of height adjustment too; 15mm of up/down movement on the back of the cradle.

Different helmets fit different people better but this amount of adjustment means most people seem to get on well with a Roc Loc 5 lid. Nearly everyone, in fact. That said, the only way to know for sure is to try one on for size.

There are a couple of other features worth noting on the fit front. First, the Aeon comes with 'slimline webbing'. It's the same width as normal, but a lighter weight and a little bit softer under your chin. Second, the little strap guides have shrunk. You can adjust them and lock them in place as easily as before though.

In terms of cooling, Giro reckon the Aeon is the equal of the Ionos. It has a hard, thermoformed skeleton within the EPS foam that Giro call Roll Cage reinforcement. It's this reinforcement (which the Prolight doesn't have) that allows them to include so much ventilation while retaining strength - and it's much lighter than the Ionos's equivalent in-mold composite sub-frame.

From wearing them one after the other, I wouldn't say the Aeon is quite as airy as the Ionos but there's really not much in it. They each offer excellent ventilation, internal channels funneling the air right across your head to keep you comfortable on hot rides.

Giro have created an excellent helmet here. Lightweight, highly adjustable and cool, this lid sets a new standard at the top end of the market. The only downside is that it's pretty darn expensive.

Available in three sizes and eight different finishes

Verdict

Lightweight, highly adjustable and well ventilated, this helmet sets a new standard at the top end of the market