The Giro Aries Spherical represents the pinnacle of road racing helmet technology, according to Contender Bicycles, with Virginia Tech lab tests showing it tops all other bike helmets in safety ratings. The helmet features Giro's proprietary Spherical MIPS system combined with 24 vents and AURA II Reinforcement Arch for optimal breathability and protection. YouTube tester Guy Kesterman praised it as the lightest, fastest, and safest helmet ever made by the brand, weighing just 265 grams for medium size. While it excels in safety and comfort, its compact design may not suit all head shapes, and its premium features come with a higher price tag. This helmet is ideal for serious cyclists seeking maximum protection and performance.
Full review
Safety and Protection
The Giro Aries Spherical stands as a pinnacle of modern helmet safety, earning Virginia Tech's highest rating among 115 tested models, including road, MTB, urban, and multi-discipline helmets. This achievement places it at the top of the safety rankings, surpassing even the previously dominant off-road helmet. The helmet's protection stems from its proprietary Spherical Technology, which incorporates MIPS (Multi-directional Impact Protection System) in a unique ball-and-socket design. Unlike traditional MIPS systems that use a sliding liner, the Aries features a dual-shell construction where the outer shell rotates independently of the inner shell during impact, redirecting rotational forces away from the brain. This design uses Progressive Layering with dual-density Nanobead EPS foam to manage both high- and low-speed impacts effectively. The system is designed to reduce peak rotational forces experienced in crashes, a key benefit that independent testing confirms. Professional reviewers like those from Cyclist.co.uk noted that Giro's claims about improved comfort and ventilation without compromising safety appear to be accurate, with the Aries delivering what Virginia Tech's lab considers the most protective helmet ever tested.
Ventilation and Cooling Performance
Ventilation represents the Aries' most distinctive feature, with 24 strategically placed Wind Tunnel vents that maximize airflow across the helmet's surface. The design incorporates a deep internal channeling system that works in tandem with these external vents to force cool air over the scalp and exhaust heat and stale air. Outdoor Gear Lab's review highlighted that the Aries delivers 'absolutely excellent ventilation' with a 'great impact test' and 'light weight,' with their overall score of 76 placing it second among 11 helmets tested. Road Bike Action noted the helmet's exceptional airflow, stating it was 'one of the most well-ventilated helmets we've ridden,' with cooling being a primary goal during development. The Aries achieves this through massive channels atop the helmet that draw air through the shell, with heat escaping through five inner channels. This ventilation system is further enhanced by the Aura II Reinforcement Arch, which allows for bigger vents while maintaining structural integrity. Testers reported that the helmet's cooling performance was particularly effective during long rides in high temperatures, with the DryCore sweat management system helping to redirect moisture away from the brow and into the sides of the face, preventing sweat from dripping into the eyes.
Comfort and Fit
Comfort in the Giro Aries Spherical is achieved through a combination of innovative design elements and traditional fit mechanisms. The helmet utilizes Giro's Roc Loc 5+ Air fit system, which provides excellent adjustability with a small dial for circumference tightening and three height adjustment options spaced about 5mm apart. The fit system is described as 'superb' by Cyclist.co.uk's reviewer, with the retention system using sturdy but supple plastic bands that evenly wrap the head. The helmet's design includes a 1-inch, 30-millimeter forehead pad with open slots that sits about 5mm from the shell, creating a sensation that the helmet isn't present on the head. This effect is particularly pronounced in the Aries compared to other helmets, with In The Know Cycling noting that despite the Aries weighing 278g (medium size), it feels lighter than competitors like the Trek Velocis (306g) and Specialized S-Works Prevail 3 (320g). The helmet's fit is further enhanced by a width adjustment of about 40mm in the plastic circumference strap, which allows for better alignment with different head shapes. The overall comfort is described as 'pillowy soft' against the skin, and the DryCore system is credited with reducing sweat dripping onto sunglasses, a feature that was particularly appreciated in hot weather conditions.
Design and Build Quality
The Aries Spherical features a sleek, aerodynamic design that represents a significant evolution from its predecessor, the Aether Spherical. The helmet's profile is described as 'lower and narrower' with a more compact form factor, achieved through the Aura II Reinforcement Arch that runs throughout the helmet's shell. This arch, made of shatter-resistant and translucent polycarbonate, provides structural integrity while allowing for larger vents. The Aries uses in-mold construction with a material composition of 43% EPS, 30% PC, 11% Nylon, 4% Polyester, 2% POM, 3% PU, 3% Fiberglass, and 1% Silicone, resulting in a high-quality finish that is uniformly neat and clean. The build quality is described as 'unequivocally high' with few areas prone to aging or damage, such as thin shell strips or exposed EPS that could dent. The helmet's aesthetic appeal is enhanced by reflective details that improve nighttime visibility, and integrated eyewear docking ports with rubber grippers that help secure sunglasses. The design also includes a DryCore sweat management system that uses an internal silicone bead to redirect moisture away from the rider's brow, and the helmet's internal channeling system works in conjunction with the vents to provide remarkable cooling power.
Weight and Performance
Despite its advanced safety features and extensive ventilation system, the Giro Aries Spherical maintains a relatively lightweight profile. The medium size weighs 278 grams according to Road Bike Action's testing, though this is 17 grams heavier than the Aether Spherical in the same size. The Aries is also 50 grams heavier than some main competitors, yet the added weight is barely noticeable due to its exceptional comfort and the way it feels like it isn't there on the head. This sensation is attributed to the helmet's innovative design elements, including the DryCore sweat management system and the way the various fit adjustments work together to create a seamless experience. The helmet's weight distribution is described as 'lighter' by In The Know Cycling, with the Aries feeling significantly lighter than its actual weight due to the design elements that minimize the sensation of bulk. The Aries' performance in terms of weight is balanced against its superior ventilation, safety features, and comfort, making it a compelling choice for riders who prioritize these aspects over absolute minimal weight.
Where It Falls Short
Despite its many strengths, the Giro Aries Spherical has notable drawbacks that may deter some potential buyers. The most significant criticism comes from its weight, which is 278 grams for a medium size, making it 17 grams heavier than the Aether Spherical and 50 grams heavier than some competitors like the Trek Velocis and Specialized S-Works Prevail 3. This added weight, while not noticeable in terms of comfort, may be a concern for competitive riders who prioritize minimal weight. Additionally, the helmet's premium price point of $350 makes it significantly more expensive than many alternatives, which may not justify the additional features for casual riders. The Aries also lacks some of the more advanced features found in other high-end helmets, such as integrated communication systems or advanced aerodynamic testing results. Some reviewers noted that while the helmet performs exceptionally well in terms of ventilation and safety, the complexity of its design may lead to manufacturing inconsistencies, though this hasn't been widely reported in user experiences. The helmet's price point and weight are the primary concerns that reviewers have raised, with some suggesting that the Aries might be overpriced for its features compared to alternatives that offer similar performance at lower costs.
Who It's Best For
The Giro Aries Spherical is best suited for riders who prioritize safety, ventilation, and comfort over absolute minimal weight or cost. It's particularly ideal for long-distance road cyclists who spend extended periods in hot weather conditions, where the helmet's exceptional ventilation system will provide significant comfort benefits. The helmet's superior safety ratings and innovative Spherical Technology make it an excellent choice for competitive cyclists who want the highest level of protection without compromising on performance. Cyclist.co.uk's reviewer noted that the Aries is 'sleek, airy, and comfortable,' making it suitable for both professional and recreational riders. The Aries is also well-suited for riders who frequently wear sunglasses, as the integrated eyewear docking ports and DryCore system help prevent sweat from dripping into their eyes. However, the helmet may not be ideal for budget-conscious consumers or those who prioritize minimal weight above all else. The premium price point of $350 makes it less accessible to casual riders, and the added weight may be a disadvantage for competitive cyclists who need every gram optimized. The Aries is best for riders who value a combination of advanced safety features, superior ventilation, and comfort in a premium helmet that performs well in all conditions.
How It Compares to Alternatives
The Giro Aries Spherical stands out in the premium helmet market, particularly when compared to its predecessor, the Aether Spherical, and competitors like the Trek Velocis and Specialized S-Works Prevail 3. While the Aether was already a lightweight and breathable helmet, the Aries improves upon it with enhanced ventilation and a more aerodynamic profile. The Aries' Spherical Technology, which incorporates MIPS in a unique ball-and-socket design, provides superior protection compared to traditional MIPS systems used in other helmets. However, it's 50 grams heavier than some competitors like the Trek Velocis (306g) and Specialized S-Works Prevail 3 (320g), which may be a disadvantage for competitive cyclists. The Aries' superior ventilation system, with 24 vents and deep internal channeling, outperforms most competitors, though the added weight and premium price point of $350 may not justify the additional features for casual riders. Outdoor Gear Lab's review placed the Aries second among 11 helmets tested, highlighting its excellent ventilation and impact test results, though it was slightly behind the top-rated helmet in their testing. The Aries' unique combination of safety, ventilation, and comfort makes it a strong contender in the premium market, particularly for riders who prioritize these features over absolute minimal weight or cost.
Strengths
- +Top safety rating from Virginia Tech labs, outperforming all other bike helmets in every category
- +24 vents with deep internal channeling for superior breathability and cooling
- +Spherical MIPS system with Progressive Layering Nanobead EPS foam for enhanced impact protection
- +Lightweight at 265 grams (medium size) making it virtually unnoticeable on the head
Watch-outs
- −More compact design may not suit all head shapes or sizes
- −Higher price point due to advanced safety and ventilation technologies
How it compares
The Giro Aries Spherical outperforms the Trek Starvos WaveCel helmet in safety ratings and ventilation, with a lighter weight and more advanced Spherical MIPS system. While the Starvos offers impact protection, the Aries Spherical provides superior breathability and a more aerodynamic fit, making it ideal for serious cyclists.
Who this is for
At a glance: serious cyclists seeking maximum performance.
Why you’d buy the Giro Aries Spherical
- Top safety rating from Virginia Tech labs, outperforming all other bike helmets in every category.
- 24 vents with deep internal channeling for superior breathability and cooling.
- Spherical MIPS system with Progressive Layering Nanobead EPS foam for enhanced impact protection.
Why you’d skip it
- More compact design may not suit all head shapes or sizes.
- Higher price point due to advanced safety and ventilation technologies.
Rating sources
“The Aries almost makes all other road helmets look outdated, when in direct comparison, it isn't even fair to put another helmet against it.”
“Although not the lightest, the Aries is sleek, airy and comfortable”
Our 4.7 score is the average of these published ratings. Ratings marked * were derived from the reviewer’s written analysis or video transcript — the publisher didn’t print an explicit numeric score, so we inferred one from their own words. Click through to verify. More about methodology.
