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Giro Aether MIPS Review: The Best Road Bike Helmets of 2021 – Cycling Helmet Review

Top Pick for Safety at the Risk of Breaking the Bank

  • Comfort, Fit, and Adjustability 100% 100%
  • Weight 70% 70%
  • Ventilation 80% 80%
  • Aerodynamics 90% 90%
  • Safety Tech and Additional Features 100% 100%

Price: $345.00

Weight: 267g

Vents: 11

Fit System: Roc Loc 5+ Air

Safety Tech: MIPS Spherical

What We Like: MIPS Spherical, Roc Loc 5+ Air Fit Retention System

What We Don’t: Staggering Price Tag

The Giro Aether is a top of the line helmet in every way. While the Synthe MIPS would be the premium helmet in most companies’ lineup, Giro one-ups the already impressive Synthe with the Aether, which features the new MIPS Spherical safety technology, and Giro claims that it is even more aerodynamic than the Synthe. All of that said, it comes with a whale of a price tag, but for some, the added safety and features will be worth the money.

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Compare to Similar Products

See Our The Best Road Bike Helmets of 2021: Cycling Helmet Review!

POC Ventral SPIN

  • Comfort, Fit, and Adjustability 100% 100%
  • Weight 70% 70%
  • Ventilation 90% 90%
  • Aerodynamics 100% 100%
  • Safety Tech and Additional Features 100% 100%

Pros

Unparalleled Combination of Weight

Safety

Ventilation

Cons

Price

Weight: 280g

Vents: 14

Fit System: Proprietary 360 Degree Retention System

Safety Tech: SPIN

Giro Synthe MIPS

  • Comfort, Fit, and Adjustability 100% 100%
  • Weight 70% 70%
  • Ventilation 80% 80%
  • Aerodynamics 90% 90%
  • Safety Tech and Additional Features 90% 90%

Pros

Highly Adjustable

Well Ventilated

Aerodynamic

Great Sale Prices

Cons

MSRP is Nearly as Expensive as the POC Ventral Spin

Weight: 268g

Vents: 26

Fit System: Roc Loc 5 Air

Safety Tech: MIPS

Lazer Z-1 MIPS

  • Comfort, Fit, and Adjustability 90% 90%
  • Weight 60% 60%
  • Ventilation 100% 100%
  • Aerodynamics 60% 60%
  • Safety Tech and Additional Features 90% 90%

Pros

MIPS

T Pro

Highly Adjustable

Magneto Eyewear Doc

Cons

Heavy

High MSRP

Weight: 284g

Vents: 31

Fit System: ARS Advanced Rollsys System

Safety Tech: MIPS, T Pro

Giro Aether MIPS

  • Comfort, Fit, and Adjustability 100% 100%
  • Weight 70% 70%
  • Ventilation 80% 80%
  • Aerodynamics 90% 90%
  • Safety Tech and Additional Features 100% 100%

Pros

MIPS Spherical

Roc Loc 5+ Air Fit Retention System

Cons

Staggering Price Tag

Weight: 267g

Vents: 11

Fit System: Roc Loc 5+ Air

Safety Tech: MIPS Spherical

Smith Trace MIPS

  • Comfort, Fit, and Adjustability 90% 90%
  • Weight 70% 70%
  • Ventilation 60% 60%
  • Aerodynamics 90% 90%
  • Safety Tech and Additional Features 100% 100%

Pros

Top of the Line Safety Features

Improved Ventilation Over Smith Overtake

Cons

Still Not the Best Ventilation

Price

Weight: 280g

Vents: 18

Fit System: VaporFit

Safety Tech: MIPS, Koroyd

Giro Foray MIPS

  • Comfort, Fit, and Adjustability 80% 80%
  • Weight 60% 60%
  • Ventilation 70% 70%
  • Aerodynamics 80% 80%
  • Safety Tech and Additional Features 80% 80%

Pros

Premium Features at a Budget Price

Cons

Doesn’t Vent or Fit Quite Like the Giro Synthe

Weight: 298g

Vents: 21

Fit System: Roc Loc 5

Safety Tech: MIPS

Bell Stratus MIPS

  • Comfort, Fit, and Adjustability 80% 80%
  • Weight 60% 60%
  • Ventilation 70% 70%
  • Aerodynamics 70% 70%
  • Safety Tech and Additional Features 70% 70%

Pros

Premium Features in a Mid Priced Helmet

Cons

Lacks Some of the Safety Features of the Bell Z20 MIPS

Weight: 296g

Vents: 18

Fit System: Float Fit

Safety Tech: MIPS

Kask Valegro

  • Comfort, Fit, and Adjustability 80% 80%
  • Weight 90% 90%
  • Ventilation 100% 100%
  • Aerodynamics 70% 70%
  • Safety Tech and Additional Features 50% 50%

Pros

Lightweight

Great Ventilation

Cons

No MIPS

Issues With Octo Fit Retention System

Weight: 234g

Vents: 37

Fit System: Octo Fit

Safety Tech: In Molding, MIT

Kask Protone

  • Comfort, Fit, and Adjustability 80% 80%
  • Weight 80% 80%
  • Ventilation 70% 70%
  • Aerodynamics 90% 90%
  • Safety Tech and Additional Features 50% 50%

Pros

Highly Adjustable

Aerodynamic

Cons

No MIPS

Falls Short of the Giro Synthe’s Adjustability and Ventilation

Weight: 248g

Vents: 20

Fit System: Octo Fit

Safety Tech: In Molding, MIT

Bell Z20 MIPS

  • Comfort, Fit, and Adjustability 90% 90%
  • Weight 50% 50%
  • Ventilation 80% 80%
  • Aerodynamics 70% 70%
  • Safety Tech and Additional Features 80% 80%

Pros

Float Fit Race Retention System

Ventilation

Cons

Weight

Nowhere to Stash Sunglasses

Weight: 305g

Vents: 18

Fit System: Float Fit Race 

Safety Tech: MIPS

Kask Mojito X

  • Comfort, Fit, and Adjustability 70% 70%
  • Weight 100% 100%
  • Ventilation 60% 60%
  • Aerodynamics 60% 60%
  • Safety Tech and Additional Features 50% 50%

Pros

Solid Performer in Every Category

Cons

Doesn’t Vent or Fit Quite Like the Giro Synthe

Weight: 220g

Vents: 26

Fit System: Up & Down Fit System

Safety Tech: MIT, In Molding

Comfort, Fit, and Adjustability

Like the Giro Synthe MIPS’ Roc Loc Air retention system, the Roc Loc 5+ Air Fit found in the Giro Aether wraps all the way around your head, leaving the helmet to float freely, rather than attaching at the temples, which is where most retention bands attach. This means that the Giro Aether does a much better than average job of conforming to different head shapes. It also keeps the helmet from creating pressure points at the temples, as well as from pulling the helmet too far forward when tightened.

The Roc Loc 5+ Air Fit system also allows for three different points of vertical adjustment, as well as the ability to adjust the “wings” on the back of the harness individually, which those of us with lumpier than average heads are sure to appreciate.

Meanwhile, there is nothing fancy about the straps, but they do their job well enough. However, for the price, we would like to see something a bit nicer, like those found on the POC Ventral Spin or Kask Protone.

Weight

Weighing in at 267g, the Giro Aether is almost exactly the same weight as the Giro Synthe MIPS, which is all the more impressive due to its increased safety features.

Ventilation

Unlike the Giro Synthe, the Giro Aether was not designed to be an aero helmet, which means that all of its vents and surface area are bent toward increasing ventilation, and Giro claims that is it 2.5% cooler than the Synthe. While we would be hard pressed to tell a 2.5% difference, either way, the Giro Aether’s 11 vents are large and channel air well through the interior of the helmet, proving that there is much more to making a well-ventilated helmet than the number of vents that it sports.

Safety Tech and Additional Features

This is where the Giro Aether really shines and what landed it our top pick for safety innovation. Giro was an early adopter of MIPS, and now an early adopter of the new MIPS Spherical system, which we previously tested in the Bell Super DH convertible mountain bike helmet. Personally, I thought so highly of the MIPS Spherical system that I made the Bell Super DH my go-to helmet for mountain biking, and the system works just as well, if not better, in the Giro Aether road helmet.

Rather than the plastic slip plane that comprises the normal MIPS insert, MIPS spherical is actually made from two different helmet shells. The shells are held together by a series of rubber bands, and the inner shell can rotate inside the outer shell to absorb rotational impacts, very much like a ball and socket joint.

While we have no hard data to certify that it is safer than your standard MIPS insert, it certainly makes sense that it would be, and we have spoken with multiple engineers who gave the system their endorsement.

This also solves some of the issues that can arise from sticking a MIPS liner in an already designed helmet, such as hair pulling, interrupted ventilation, and squeaking.

All said, if we had to choose a single helmet based solely on its safety technology, we would go for the Giro Aether and its MIPS Spherical system just ahead of the POC Ventral Spin’s Spin system.

The Aether also features the same multiple density EPS foam construction found on the Synthe, and its “two” shells are actually comprised of six individual pieces of multiple density eps foam, all designed to function together and crumple in precise ways to best absorb impacts.

Aerodynamics

We mentioned earlier that the Giro Aether was designed with safety and ventilation in mind, not aerodynamics. This makes it quite surprising that Giro claims that wind tunnel testing actually shows the Aether to be slightly more aerodynamic that the Giro Synthe, which was designed to be aerodynamic. Perhaps this lends some credence to POC’s idea that it is better to let air pass through a helmet than to pass around it. Whatever the case, its aerodynamic nature is just one more feather in the cap of a helmet that really seems to do it all.

The Bottom Line

The Giro Aether is a helmet that is impressive in just about every way. It is fairly light, extremely well ventilated, more aerodynamic than helmets designed with aerodynamics as a priority, it features one of the best fit systems on the market, and its MIPS spherical safety technology is among the most innovative helmet features that we have ever seen. 

Naturally, there is a catch. The Giro Aether retails for a whopping $345, and while it can be found cheaper, you are still likely to pay over $300 for it. Now, we would consider this a huge investment in a helmet that, like all helmets, is only designed to keep you safe in one crash. However, you only get one head, and its unbeatable safety combined with its strong performance across every category will no doubt have some riders shelling out the big bucks for the Giro Aether.

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We participate in affiliate programs to help us fund Gear Hacker. Some of the links in this website are affiliate links, which means that if you purchase a product using our link, we will earn a small commission. Don’t worry! This comes at no additional cost to you, and we will never base our reviews on whether or not we earn a commission off of a product. With that said, if you find our review helpful and decide to purchase an item we review, we would be very appreciative if you use our links to do so. It will help us bring you more awesome content in the future!