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Giro Aries Spherical Helmet



Very light and well ventilated, with excellent safety credentials, ideal for the warmest days
Very light
Great for warm weather and heavy sweaters
Shape might not suit everyone

At every product is thoroughly tested for as long as it takes to get a proper insight into how well it works. Our reviewers are experienced cyclists that we trust to be objective. While we strive to ensure that opinions expressed are backed up by facts, reviews are by their nature an informed opinion, not a definitive verdict. We don't intentionally try to break anything (except locks) but we do try to look for weak points in any design. The overall score is not just an average of the other scores: it reflects both a product's function and value – with value determined by how a product compares with items of similar spec, quality, and price.

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The Giro Aries Spherical is the company's latest pro-level helmet, featuring its Spherical Technology system, a unique ball-and-socket design that adds more safety on top of Mips. As well as ranking as one of the safest helmets out there, the Aries is also one of the lightest helmets on the market, and the abundant vents definitely make it one of the coolest I've used. It does, however, come at a high price.

For other (cheaper) options, check out our guide to the best lightweight road cycling helmets.

The Aries launched in the spring of this year, and at the time of receiving my test helmet it was a little bit too cold for the lid. That is because it is indeed very well ventilated with a total of 24 "wind tunnels".

Two-part construction

The most striking feature of the Aries helmet is the way it is constructed – as with any Giro (or Bell) helmet with this Spherical Technology. It was developed at the Bell+Giro Dome in partnership with Mips, though describing it as basically a 'ball-and-socket design' doesn't really capture the way you can actually see the two parts of the helmet move in real life. We've seen it used in other helmets we've tested – the Giro Helios Spherical that Anna reviewed in 2021, and the Bell XR Spherical Road Helmet that George tested in January.

2023 Giro Aries Spherical Helmet - Mips.jpg

Overall, the Aries is very well made, and Giro has managed to keep it very small despite the number of vents and safety features. The open structure has been made possible by the Aura II Reinforcement Arch – it's the translucent and shatter-resistant support that runs over the top of the helmet and adds extra structure.

2023 Giro Aries Spherical Helmet - vent detail 1.jpg

The Aries has a few more features than the Aether, Giro's previous benchmark for a premium road racing helmet, and although the Aether was already ranking pretty well, the Aries takes things further. It's claimed to offer a five per cent weight saving, a four per cent reduction in aerodynamic drag and over two per cent better cooling. It's also ranked at the very top of the Virginia Tech helmet testing list, beating even full-face helmets with its Spherical and Mips safety tech combo.

The safety credentials, considering the very light weight of the helmet (a claimed 265g for a medium – though that's what our small weighed), are very impressive and made wearing the helmet a little bit more pleasant – knowing that my head was so well protected. The lightness of the helmet made it an especially great choice for longer rides when you want to eliminate any weight on your neck. It's so light that it's almost unnoticeable.

2023 Giro Aries Spherical Helmet - front.jpg

The Aries uses the minimal Roc Loc 5+ Air Fit system that allows for 1.5cm of vertical and 4cm of horizontal adjustment, plus a dial to control the circumference. For those with long hair, the system also has a big enough hole above the dial so you can slot your ponytail out.

2023 Giro Aries Spherical Helmet - tension system.jpg

The straps are very soft and thin and have Y-shaped anchors, so they keep clear of the ears. A minor niggle with the straps is that they have no end cap, which means you can pull the buckle off by accident.

2023 Giro Aries Spherical Helmet - strap.jpg

Best for warm weather

Because of the well-ventilated structure of the Aries, I found it best suited for double-digit temperatures. Even on the hottest of days, the vents kept my head (despite also having long hair) significantly cooler and less sweaty than any other helmet I've tried.

2023 Giro Aries Spherical Helmet - rear.jpg

Giro has also equipped the helmet with a DryCore brow pad which was very effective at keeping sweat from dripping into my eyes, even when things got really hot. It absorbed all sweat, and when trying a "helmet squeeze', nothing dripped out.

2023 Giro Aries Spherical Helmet - logo detail.jpg

Elsewhere on the helmet, the pads are infused with "pure silver" – according to Giro – which should help keep them odour free. I can confirm that the pads did indeed not smell despite multiple very sweaty rides.

Shape isn't for everyone

Helmets differ in their shape to suit different head shapes, and what fits one person might not feel comfy for another. I found the Aries a little uncomfortable – as if it could be too small despite the small size being just right on paper for my head. I get along really well with Met and Poc helmets in the same size, so I think the slight discomfort from the Aries is because of its shape. It wasn't so uncomfortable that it caused any pain, but I had some proper brow-pad indents on my forehead after a long ride.

2023 Giro Aries Spherical Helmet - inside.jpg

As with any helmet, I would recommend trying before buying, preferably in two different sizes. For me, the medium would be too large; the small was better despite it being a bit snug.

Value & conclusions

The excellent performance of the Aries is not exactly a surprise considering its high price of £289.99. That puts it in line with helmets such as the Met Trenta 3K Carbon Mips at £290 (up a tenner since Jamie tested it last year) and the S-Works Prevail 3 at £275 – also tested last year, by Stu. The Met is even lighter than the Aries, and the S-Works only marginally more (and that's in a medium).

These three helmets offer the same selling points: light weight, good ventilation and extra safety tech. Arguably, the Aries tops the bunch on the safety front, and because I have been swapping between the Met and the Aries during the last few months, I can confidently say the Aries also feels significantly cooler in hot weather.

It does come with a high price tag, but if you can afford it – and it suits your head shape – this is an excellent helmet: very light, very well ventilated and extremely safe.


Very light and well ventilated, with excellent safety credentials, ideal for the warmest days test report

Make and model: Giro Aries Spherical Helmet

Size tested: Small

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 says: "Cooler, lighter, faster – pick all three. The all-new Aries™ Spherical is our most premium helmet ever. Its smaller form and lighter weight (only 265 grams in size medium, CE certification), delivers sensational comfort and cooling power.

Spherical Technology™, the ball-and-socket design powered by Mips® adds protection by redirecting energy away from the brain in certain impacts, and Progressive Layering with dual densities of Nanobead EPS foam adds more comprehensive energy management.

24 Wind Tunnel vents are maximized by the AURA Reinforcement Arch, while plush Ionic+ anti-microbial padding and a network of intricately engineered deep internal channelling elevate comfort.

From the proven reliability and adjustability of the Roc Loc® 5+ Air fit system, to full lower hardbody coverage to enhance durability, to the meticulous production quality, the Aries is the epitome of top-shelf performance, protection, and style."

Tell us some more about the technical aspects of the product?

Giro lists:






Rate the product for quality of construction:
Rate the product for performance:
Rate the product for durability:
Rate the product for weight (if applicable)

Very light – although there are some helmets a smidge lighter.

Rate the product for comfort (if applicable)

The shape isn't ideal for my head shape, but it is still very comfy.

Rate the product for value:

It's expensive, but on a par with the Met Trenta 3K Carbon Mips and S-Works Prevail 3.

Tell us how the product performed overall when used for its designed purpose

The helmet performs excellently.

Tell us what you particularly liked about the product

The ventilation and the spherical protection.

Tell us what you particularly disliked about the product

The shape makes the helmet feel slightly smaller than others.

How does the price compare to that of similar products in the market, including ones recently tested on

It's expensive, but not alone: the Met Trenta 3K Carbon Mips is £290 and the S-Works Prevail 3 is £275.

Did you enjoy using the product? Yes

Would you consider buying the product? Probably not, but only because the shape isn't the best for my head on very long rides.

Would you recommend the product to a friend? Yes

Use this box to explain your overall score

Very light and well-ventilated helmet with excellent safety credentials for the warmest days. If the shape fits you, this is really one of the best and safest helmets out there.

Overall rating: 9/10

About the tester

Age: 30  Height: 164cm  Weight: 52kg

I usually ride: Specialized Tarmac Sl6  My best bike is:

I've been riding for: 5-10 years  I ride: Every day  I would class myself as: Expert

I regularly do the following types of riding: cyclo cross, commuting, touring, general fitness riding, mtb, Ultra-distances

Suvi joined F-At in 2022, first writing for She's since joined the tech hub, and contributes to all of the sites covering tech news, features, reviews and women's cycling content. Lover of long-distance cycling, Suvi is easily convinced to join any rides and events that cover over 100km, and ideally, plenty of cake and coffee stops. 

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