First look: New Giro Aether road helmet advances MIPS safety technology

Don’t miss out on the latest CyclingTips updates.

Jump To Comments

Giro Sport Design has a new flagship road helmet. It’s elegant. It rotates. It’s pricey.

It’s called the Aether. It looks like Giro’s Synthe, with a few subtle improvements — and one very significant development. The current Synthe MIPS has a conventional low-friction, thin plastic “slip plane” placed in between the foam liner and the retention system. But the new Aether utilizes something Giro and MIPS have developed in partnership over the past three years, which they’re calling MIPS Spherical.

First seen in Giro’s Avance MIPS snow helmet, MIPS Spherical takes the concept of protecting the brain from rotational forces to the next level.

Giro Aether MIPS

What it is: The Aether is Giro’s new flagship road helmet, incorporating proprietary MIPS Spherical technology — two separate layers of foam held together with an elastomer attachment that rotate independently of a rider’s head. Giro claims MIPS Spherical is its best integration of MIPS yet in terms of comfort, ventilation, and aerodynamics.
What it is not: Aesthetically, the Aether is not a radical departure from Giro’s Synthe model. It is not a replacement for the Synthe, which drops in price from US$270 to US$220. It is not positioned as an “aero road” helmet.
Who’s wearing it: BMC Racing Team, Canyon-SRAM, Clif Pro Team,
What it weighs: 250g
What it costs: US$325 / AU$475 / €299
When it’s available: August 1, 2018

The other common alternative to those standard MIPS plastic liners is to integrate the slip plane directly into the retention system, like Giro has done with the RocLoc Air in the new Vanquish aero road helmet, and the similar Float Fit system in the Bell Zephyr. But with Spherical MIPS, there’s instead an elastomer attachment placed between two layers of expanded polystyrene foam — the internal liner and the outer shell — allowing them to rotate independently during an angled impact.

As with all MIPS systems, the goal is to minimize how much the head violently twists upon impact, with the theory being that reducing how much the brain abruptly spins inside the skull helps to prevent brain trauma. Though the full product name of the helmet is Aether MIPS, that’s a bit redundant; unlike with other Giro models, there is no non-MIPS Aether. This helmet only exists because of MIPS Spherical technology; it’s in the DNA of the design.

The result is a MIPS system that spans the entire inner liner of the helmet, yet is invisible to the naked eye, with claims of better ventilation, lighter weight, improved comfort, and increased aerodynamics over the Synthe. Also increased? The price. We’ll get to that a little later. But first, the backstory.


For all the R&D Giro has put into MIPS Spherical, they are not here to tell you it’s a safer helmet. It might be safer, but you didn’t hear that from them. For legal reasons, Giro — like most manufacturers — will not make specific claims about helmet safety. Every crash is different, every brain injury is different, and in-house attorneys warn against making promises to consumers about the performance of a helmet in an accident.

What Giro will say, however, is that within the constraints of laboratory testing, test engineers were able to see “repeatable benefits” with the MIPS Spherical system — a technology first incorporated into its US$600 Avance snow sports helmet in 2016, which was designed to protect against both high-speed crashes on ice as well as repetitive gate impacts during slalom racing.

Instead, Giro and MIPS are eager to tell the story of how much science and research goes into developing their products. That research includes three in-house tests that Giro began developing five years ago to help prove or disprove the MIPS concept — tests based around rotational, rather than linear, impacts.

The vision behind MIPS (Multi-Directional Impact Protection System) began in 1995 when Hans von Holst, a Swedish brain surgeon, repeatedly found himself operating on trauma victims who had been wearing helmets when their heads hit the ground; their skulls were not fractured, but they had still suffered brain injuries. Von Holst contacted the Royal Institute of Technology in Stockholm and began research into head and neck injury prevention.

After conducting thousands of helmet tests, Holst and partners Peter Halldin and Svein Kleiven determined that most accidents result in oblique impacts — meaning slanted, neither parallel nor at a right angle — which causes rotational violence to the brain.

Existing helmets may have done their job in protecting the skull, but they weren’t doing enough to protect the brain, which is more sensitive to internal shear than to linear impacts. The human brain is soft, like gelatin or tofu, and suspended in cerebrospinal fluid. It doesn’t compress, but when your head violently rotates in an impact, different layers of the brain will accelerate at different rates. As a result, the billions of tiny nerve cells that comprise the brain can stretch and tear.

Yet, until recently, traditional helmets had historically only been tested for linear impact, not those more complex forces that occur when sliding or twisting. The first prototype of a MIPS-equipped helmet was tested at the University of Birmingham in 2000, but it would be another decade before it was embraced by the cycling industry.

Some might suggest that MIPS is no more than a marketing gimmick, but recent data says otherwise. In an independent study released last week, developed by Virginia Tech university and the US-based Insurance Institute for Highway Safety (IIHS), helmets were ranked on the theoretical risk of concussion based on a more modern test protocol; the lower the percentage, the higher the ranking. The first 30 helmets to be included in the test covered a spectrum of prices and styles, but only four earned the top five-star rating: the Bontrager Ballista MIPS, the Louis Garneau Raid MIPS, the Bell Stratus MIPS, and the Specialized Chamonix MIPS. The top six rated helmets all use MIPS technology, and none of the bottom 10 were equipped with MIPS technology.

Granted, the study didn’t directly compare MIPS and non-MIPS versions of the same helmet, so it’s not 100% conclusive that adding MIPS makes a helmet safer. But it’s powerful circumstantial evidence.

The relationship between Giro and MIPS has grown so close over the last five years that former Giro general manager Greg Shapleigh, who had been with the brand since 1990, left to join MIPS last summer.

At a June product launch for the Aether in Scotts Valley, California — just outside of Santa Cruz — Shapleigh was on hand to speak about MIPS and the brand’s partnership with Giro in developing the Aether’s MIPS Spherical technology.

“MIPS is thrilled to have a partner like Giro,” said Shapleigh, who acknowledged that during his time at Giro, the helmet brand originally expressed skepticism of MIPS technology. “While some partnerships between MIPS and helmet brands are more commercial, this is more of a collaborative partnership, and MIPS only has a few of those. There’s no financial arrangement, and we know that Giro will use whatever works best. But our mindset is the same — to reduce the risk of brain injury.”

To those who still aren’t convinced, here’s how Eric Richter, Giro’s senior brand and business development manager, addresses that cynicism: “We all ride. Our friends ride. Our families ride. There is no reason for us to create anything less than our very best.”


Inside Giro headquarters in Scotts Valley is the DOME test lab — DOME is an acronym for Design, Observation, Materials, Engineering — which includes text fixtures, 3D printers, injection- and thermal-molding equipment, an in-house wind tunnel, CNC machines, and more. The test lab is shared by Vista Outdoor brands Bell, C-Preme, and Giro, and is used to design, develop, and evaluate helmets for power sports, cycling, and snow sports.

Among the text fixtures demonstrated to the media during a tour of the DOME in June were the BRAD, Mono-rail, and Sled, all designed to evaluate how well helmets manage rotational motion. From an engineering perspective, MIPS defines rotational motion as “a combination of rotational energy (angular velocity) and rotational forces (angular acceleration) that both affect the brain and increase the risk for minor and severe brain injuries.”

After Giro was first approached by MIPS, following a period of review and discussion, DOME engineers sought a second opinion. They reached out to a Phoenix-based crash-testing lab called Exponent, where hundreds of crash-test dummies have their heads repeatedly slammed and twisted for test purposes. Exponent’s testing confirmed that MIPS technology was effective, and DOME and Exponent began designing their own rotational-test lab equipment, as none was on the market. In 2014, Giro unveiled its first MIPS-equipped helmets.

Early research MIPS had conducted determined that most often during crash, brain injuries occur when the head strikes at an angle. Simulating that angular impact allows Giro, and MIPS, to develop ways to redirect and attenuate, or absorb, the energy of an angled impact.

The BRAD test uses a helmeted 105-pound Biofidelic Rotational Anthropomorphic Dummy [BRAD], complete with head, articulating neck, and torso, that swings from the ceiling into an inclined ramp to measure rotational violence. The body mass assumes the size and weight of a 50th percentile adult, with an accurate center of gravity. To simulate how a helmet, and brain, might fare upon striking asphalt, sandpaper is applied to the surfaces where the helmets impact the test fixtures.

Video: The BRAD test fixture

The Mono-Rail test drops a helmeted head form onto an angled, stationary surface, replicating an oblique impact. The head form can be placed at different orientations: frontal, 90 degrees, tilted, or anywhere in between. The test is run with MIPS protection and without, with the aim of targeting a 30% reduction in angular violence.

Video: The Mono-rail test fixture

The Sled test sees a helmeted head form on a timed drop into a sliding plate, or sled; the impact causes the head form and helmet to rotate, simulating the impact of a crash. It uses a specific velocity to replicate a 30-degree impact trajectory — the angle at which many helmets impact the ground.

Video: The Sled test fixture

Combining data from these tests, Giro is able to determine how effective the MIPS system is and what can be done structurally to reduce rotational violence to the brain.


Over two days of riding near Giro’s headquarters in Scotts Valley, I rode the Aether in conditions that varied from 27°C (80°F) on a long, exposed climb in the afternoon to 7°C (45°F) along the coast during a morning roll-out.

Like the Synthe, the Aether is light, aerodynamic, and well ventilated. Deep internal channels in the liner create airflow over the scalp, and without the usual MIPS plastic liner, that air can now come into direct contact with your head. Giro claims the Aether surpasses the Synthe MIPS in all departments, including a 2.4% improvement in aerodynamic efficiency and 2.5% better cooling.

Climbing in direct sunlight, with little to no breeze, the Aether kept my head cool, comfortably. I never thought about it once, which is in some ways the highest praise you can give a helmet while suffering on a hot climb. I’ll need to wear it on a longer, hotter day to see if I can feel a difference, but the deep, unobscured channels certainly seem more effective.

Having worn a Synthe for the better part of the last four years, I felt right at home in the Aether. The updated RocLoc 5+ Air retention system offers a new level of vertical positioning — it slides up and down the back of the skull — and is tightened and loosened using Giro’s standard retention dial. Giro claims the new retention system offers the ability to tune the occipital contact points asymmetrically, but I haven’t figured out how, or why, I would do that. Still, the RocLoc 5+ Air retention system works, and works well.

I had no fit issues, and a perfect fit dialed in a matter of minutes, if not seconds. However, given the fact that the helmet is constructed of two independent layers of foam (which offer about 15mm of movement), the risk of rolling around impervious to a slightly cocked helmet is real. Aether owners will want to be sure to do a double take in the mirror on their way out the door.

You’d never know it on first glance, but the Aether’s outer shell is constructed of six individual pieces of polycarbonate that allow for the helmet’s wide, open vents. Asked for details on the construction, Giro said it was “not willing to share” the construction process.

One element on the Aether that stands out is the translucent Aerodynamic Ultimate Reinforcing Arch (AURA), a shatter-resistant piece of thermoplastic resin that runs across the top that connects and supports the outer shell. The AURA replaces a larger, structurally similar piece of foam on the Synthe, and contributes to the fact that the 250g Aether weighs 15g less than the Synthe MIPS. It also looks cool.

Also evident on first glance is the 3D Giro logo on the outer shell, which is laser-cut and pressed into the polycarbonate sheet from behind before it’s permanently in-molded in place. It’s a small detail, but like the AURA, it just looks sharp.

New rubber grippers placed on the outer vents help keep eyewear secure when not being worn. It’s a cool feature, though not something I personally would use often unless in a downpour or stopping for a long lunch.

The only issue I’ve had thus far with the Aether is that the MIPS system seems to yank a few hairs from the back of my head every time I take it off. That’s not unique to MIPS Spherical, and though it’s a minor annoyance, it can be a bit of a shock.

The Giro Aether will come in nine colorways, including three limited-edition colors, and a “Black Flash” reflective model.

In totality, Giro says the Aether is the “most advanced cycling helmet” the brand has ever created — a piece of equipment Giro’s senior director of marketing Dain Zaffke called a “stunning feat of engineering.”

“It took us three years to work through the design challenges,” Zaffke said. “It was touch and go; we weren’t sure we would get to this point, and at times I questioned whether we should try. I kept thinking, ‘If this won’t nail it, let’s just create a Synthe with integrated MIPS [into the retention system].’ It would have been easier to shoehorn this into a Vanquish. This is us flexing our muscle a bit.”

The Aether will be available in nine colorways, including three limited editions. The review sample provided to media at the recent product launch is a luminous matte black/blue pearl that has to be seen in sunlight to be fully appreciated. Beauty is in the eye of the beholder, but I’d suggest it’s as elegant a cycling helmet as I’ve ever worn, though the matte black/blue pearl color wouldn’t have been my first choice. That nod would go to their “black flash,” which shows as matte black in sunlight but turns fully reflective in the face of headlights. A black helmet that is more visible at night than any other color? Yes, please.


It’s impossible to view the Aether outside of the context of Giro’s four-year-old Synthe. Aesthetically, they look very similar, particularly from the front; less so from the rear. What’s different is largely under the hood.

The Aether is smaller and lighter than the Synthe. Giro claims it’s also cooler and more aerodynamic. The “is it safer?” question is a thorny one, but it stands to reason that the MIPS Spherical system offers better protection than the original MIPS slip plane used by the Synthe. When the Synthe launched in 2014, it was just as Giro was embracing MIPS, which is why the Synthe has been offered in MIPS and non-MIPS models for three years now; it was already in production, and the slip plane was an add-on.

Giro claims MIPS Spherical “improves rotational energy management” over previous MIPS systems while optimizing comfort and ventilation. It’s certainly the best-yet integration of MIPS into a road helmet. The technology is there, but you can’t see it.

The Aether does not replace the Synthe; instead, the Synthe MIPS drops in price, to US$220, and that’s an important consideration. It’s not fair to say the Aether is an updated version of the Synthe, yet outside of how they might perform in an impact, they look, feel, and perform similarly, at a cost differential of over US$100. That price difference is as inescapable as the aesthetic likeness.

For 2019, there will no longer be a Synthe model without MIPS protection. In fact, Giro claims there are now only two helmets in the brand’s entire cycling line that don’t offer a MIPS option; within the United States, every cycling helmet now comes in a MIPS version.

It’s worth pointing out that the non-MIPS Synthe earned four stars (out of a possible five) in that Virginia Tech-IIHS test, ranked 13th out the 30 helmets tested; the Synthe MIPS would be expected to score higher. I’ll be very interested to see how the Aether scores, though there’s been no timeline given as to when Virginia Tech and IIHS will conduct their next round of tests, or whether the Aether will be included.

Also, it’s worth keeping in mind is that while MIPS Spherical is proprietary to Giro, MIPS partners with dozens of other helmet brands. As Giro’s Eric Richter acknowledged, “Technically, another brand could try to replicate a spherical system using MIPS’s essential elements.” It may look different, and it may go by a different name, but we should expect to see this technology in other helmet brands in the future. Which brands, when, and what it might cost are unknowns.

So, in the context of Giro’s new flagship road model and its previous flagship road model, is MIPS Spherical and a handful of other improvements worth an additional US$105? It’s a decision every consumer will ultimately have to make for themselves. Perhaps additional testing information from Virginia Tech will eventually help bring the answer into focus. Perhaps not.

In the meantime, potential customers have to ask themselves a variation of the same question they’ve been faced with for years: What is protecting your brain worth to you? How do you put a price on it?

Just as all crashes (and brain injuries) are unique, the same can be said for account balances and financial circumstances. It’s all variable, and subjective.

If you’re sold on MIPS, you highly rate aerodynamics and ventilation, and your current helmet has seen more than two or three years of regular use, the Aether is absolutely worth consideration. If you bought your helmet in the last two years, and you’re happy with it, you can certainly get another season out of it. If you want the latest and greatest Giro and MIPS have to offer, and you’re willing to invest US$325 in head protection, the Aether awaits.

Editors' Picks