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
Lightweight, highly adjustable and well ventilated, this helmet sets a new standard at the top end of the market
road.cc test report
Make and model: Giro Aeon helmet
Size tested: Medium, red/black
Tell us what the product is for, and who it's aimed at. What do the manufacturers say about it? How does that compare to your own feelings about it?
Giro say, "Giros new high-end road racing helmet is the Aeon, pronounced 'A-on' and defined as 'a type of divine entity', and it is the ultimate combination of ventilation and light weight, smashing every other helmet out of the market
Using cutting edge technology and design to enable an industry leading combination of weight, ventilation, fit and comfort
Its Thermoformed SL Roll Cage is 49 percent lighter than the roll cage used on the Giro Ionos
24 Wind Tunnel Vents matched with deep internal channels ensures the best venting helmet in the industry
RocLoc 5 Fit System for the perfectly dialled fit without compromise
MicroTech Tri-Locs along with ultra-light slimline webbing enables the helmet to save over 36 percent of the weight of its fittings alone versus a standard performance road helmet
X-Static padding for a plush fitting, odour free helmet
Smart details using metal badging
Top spec pad-printed logos
Available in 3 Super Fit sizes to the perfect Giro shape
Certified to CE EN1078
Estimated weight for medium: 189 grams
We're talking what it's like to wear rather than what it's like to have a crash in
Again we're talking wear and tear here, not what happens in a crash. In-mould helmets do well on this score because there isn't anything to snag and in day to day use that shell should never come of. The Aeon is very well made example and indeed is probably a shade more durable than its Prolight sibling - you won't find a better made helmet
You could spend half the price and get a helmet that's maybe 80% as good... but you could say that about most high end products in cycling (and other markets too).
Tell us what you particularly liked about the product
It's so comfortable, you hardly feel you have a helmet on.
Did you enjoy using the product? Yes
Would you consider buying the product? Yes
Would you recommend the product to a friend? Yes
About the tester
Age: 40 Height: 190cm Weight: 74kg
I usually ride: My best bike is:
I've been riding for: Over 20 years I ride: Most days I would class myself as: Expert
I regularly do the following types of riding: time trialling, commuting, sportives, general fitness riding,
Mat has worked for loads of bike magazines over the past 20 years, and been editor of 220 Triathlon and Cycling Plus. He's been road.cc technical editor for seven years, testing bikes, fettling the latest kit, and trying out the most up-to-the-minute clothing. We send him off around the world to get all the news from launches and shows too. He has won his category in Ironman UK 70.3 and finished on the podium in both marathons he has run. Mat is a Cambridge graduate who did a post-grad in magazine journalism, and he is a past winner of the Cycling Media Award for Specialist Online Writer.