Giro’s new flagship road helmet, the Eclipse Spherical, delivers on the brand’s pedigree as a top-spec road bike helmet with aero credentials.

Given that Giro started the aero road revolution back in 2012 with the Air Attack helmet, any launch from the American brand should warrant attention.

And that’s exactly what the new Giro Eclipse Spherical, which debuted on the WorldTour in 2021 and is being touted as the brand’s fastest ever road helmet, demands.

Giro Eclipse Spherical specifications

When Giro officially launched the Eclipse Spherical, it made a big play of the helmet’s aerodynamic and ventilation credentials.

While aero road helmets of old may have been fast, they were prone to overheating – but not with the Eclipse, Giro says.

The Eclipse Spherical’s spec list features much of the top-end innovation we’ve come to expect on Giro’s latest helmets. There’s the Spherical technology developed with MIPS that debuted in road cycling on the Helios helmet, the Roc Loc 5 Air retention and fitting system, and plush Ionic+ internal padding.

The 17 ventilation channels should help keep your head cool.
Matt Baird / Our Media

There are 17 ventilation channels (confusingly, Giro lists 14 total vents) for aeration.

As well as the helmet’s aero claims, Giro’s own cooling efficiency testing places the Eclipse at 89.25 per cent, half a percentage point behind the 21 vents of the more climbing-focused Aether, and ahead of its own Helios (87.68 per cent) and Vanquish (85.13 per cent) helmets.

Now onto those aero claims. The Vanquish MIPS, with the shield visor in place, scored very highly in our own independent wind-tunnel testing in 2019, consistently up there with the Specialized Evade 2 across a range of yaw angles and speeds.

With the new Eclipse Spherical, Giro claims the helmet beats the (undisclosed) ‘closest aero road helmet competitor’ by 14 seconds over 100 miles (160km), riding at 25mph, and is a full 60 seconds faster than the Vanquish. That’s wind-averaged drag, with 80 per cent of the time in a typical riding position and 20 per cent in a head-down riding position.

Giro Eclipse Spherical performance

Ventilation is aided further by generous rear exhaust ports.
Matt Baird / Our Media

We’re unable to verify Giro’s claims, but 25mph is nearly twice as fast as I’d ride 160km. However, there is the argument – put forward by aerodynamicist Dan Bigham and others – that aerodynamics matter to slower cyclists at lower speeds even more, due to the extended duration out on the asphalt.

Once the excess strap had been trimmed, my time with the Eclipse Spherical was all positive.

The Roc Loc 5 Air system’s slick retention dial and internal fitting mechanism swiftly secures an ideal fit, akin to my regular Giro lid, the Agilis MIPS. The cradle slides up and down to fine-tune the fit and the grippy dial provides simple adjustment.

The padding also has a luxurious feel to it and sits in the optimum place on the forehead, providing plenty of comfort and mopping up sweat.

It’s worth noting, though, that the straps aren’t removable for washing, as on the Scott Centric Plus for example, and a chinstrap isn’t provided.

The Eclipse’s compact design features six main vents at the front, concentrated on the left and right sides, with a smooth central strip. There are also deep channels within the helmet to draw air through, and generously sized exhaust ports at the rear. All that combines to make ventilation impressive, not least for an aero helmet.

Padding and fit are impressive, although there’s no chinstrap.
Matt Baird / Our Media

The Eclipse is the latest Giro helmet to use the Spherical tech developed with MIPS. It’s the most effective integration of MIPS I’ve experienced, with two EPS (expanded polystyrene) foam liners joined by elastomer ‘anchors’ in a ball and socket construction to rotate individually of each other.

The outer shell is also integrated smoothly into the EPS core to complete a smart and classy aesthetic, although anyone wanting a hi-vis colour scheme will be disappointed by the more muted options of the Ano Blue seen here, plus black and red, charcoal, black and white options.

The inclusion of MIPS and those two EPS foam liners would suggest a weighty number, but the Eclipse Spherical comes in at 277g on our scales for a medium.

This puts it in the mid-table of aero road lids, a touch heavier than the Kask Utopia (235g, but minus MIPS) and our benchmark Specialized Evade II (262g, with MIPS), but lighter than the Bell Z20 Aero MIPS (281g), for example.

It’s a smart-looking lid, finished here in Ano Blue.
Matt Baird / Our Media

On the subject of numbers, that £239.99 price can’t be ignored. Much will depend on your own bank balance and how important shaving those seconds from your rides will be.

The price tag puts it above the Limar Air Speed (£179) and Rudy Project Nytron (£199), for example, but below the Specialized Evade II with Angi (£250).

Giro Eclipse Spherical bottom line

The low-profile design and R&D behind the Giro Eclipse Spherical have resulted in a svelte aero road helmet that also qualifies as a serious all-rounder.

We’ll have to take Giro’s wind-tunnel testing at face value, but it’s a helmet that subjectively ‘feels’ fast on the roads.

The Spherical and MIPS combination ticks the safety boxes, while the plush padding, ventilation channels and secure retention system have produced a helmet that should feel at home across a variety of conditions, locations and distances.