New Giro Eclipse Spherical Helmet – save more watts and stay cool

Faster – and more thermally efficient – than both Giro's Vanquish and Helios helmet models

New Giro Eclipse Spherical Helmet
(Image credit: Giro)

Giro, the California-based helmet (opens in new tab) and apparel (opens in new tab) manufacturer, has just released its new Eclipse Spherical Helmet, which it says is designed to be the “fastest road helmet and coolest aero road helmet in the peloton.” 

At the heart of the Eclipse Spherical are its 14 “Wind Tunnel” vents, which are designed to “pull air through the helmet” to decrease the levels of aerodynamic drag, whilst also providing a cooling power to “rival the most aggressively vented road helmets. 

Together with an outer shell which “actively streamlines airflow” to reduce drag across multiple wind angles, Giro is claiming the Eclipse as the fastest road helmet it has ever made. 

New Giro Eclipse Spherical Helmet

(Image credit: Giro)

Regarding its safety, the Eclipse utilises Giro’s Spherical Technology, with its ball-and-socket design. This allows the helmet’s outer EPS foam liner to rotate around the inner foam liner, thereby helping to redirect impact forces away from the brain. 

Keeping the helmet in place is Giro’s Roc Loc 5 Air retention system, whilst the Ionic+ antimicrobial padding is designed to further enhance the fit and help absorb sweat and moisture.

New Giro Eclipse Spherical Helmet

(Image credit: Giro)

The claimed weight of the helmet is 275 grams in a size medium, which is respectable but not feather light. When we had POC’s Ventral aero helmet (opens in new tab) on test in a size medium, it weighed in at 251 grams. 

Five colourways are available and sizing covers small, medium and large. Pricing stands at $250.00 / £239.99 and it can be bought immediately from authorised Giro retailers as well as Giro’s own website (opens in new tab).

The testing

Backing up the claims of enhanced aerodynamics and more efficient cooling, Giro has provided a couple of charts. The first uses the performance of Giro's Aether helmet over 100 miles at 25 mph as a baseline.

New Giro Eclipse Spherical Helmet

(Image credit: Giro)

The new Giro Eclipse, being 163.5 seconds faster, would cover 100 miles in 3 hours, 57 minutes and 16.5 seconds – according to the chart. This corresponds to a speed of approximately 25.29mph.

Giro’s unnamed closest competitor, in saving 149.7 seconds over the Giro Aether, would complete the 100 miles in 03:57:30.3, putting the average speed at 25.26mph.

So that puts the new Giro Eclipse at 0.12% faster than the closest competitor – equating to about 14 seconds saved over approximately four hours. Perhaps an illustration of how marginal aero helmet gains can be, but at least for Giro: a win is a win.

New Giro Eclipse Spherical Helmet

(Image credit: Giro)

Regarding the thermoregulation, Giro has used its proprietary “Therminator” head to measure the helmet’s cooling efficiency. They found that the Eclipse is almost as efficient at cooling as the Aether helmet, whilst also being significantly more cooling than the brand’s Vanquish aero helmet – which itself didn’t prove quest as fast as the new Eclipse in Giro’s aero testing.

New Giro Eclipse Spherical Helmet

(Image credit: Giro)

In terms of how the test was performed, Once the head is heated to 100°F (37.8°C), the team turns on the wind tunnel to the testing speed (25mph) and takes temperature measurements every second for 35 minutes to arrive at the ending average temperature of the head. 

To set a baseline, the head is also measured without a helmet, with the temperature it reaches after the 35 minutes taken as 100 percent effective cooling.

But real test will be how the helmet performs in person – watch this space for our review. 

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Starting off riding mountain bikes on the South Downs way, he soon made the switch the road cycling. Now, he’s come full circle and is back out on the trails, although the flat bars have been swapped for the curly ones of a gravel bike.


Always looking for the next challenge, he’s Everested in under 12 hours (opens in new tab) and ridden the South Downs Double in sub 20 (opens in new tab). Although dabbling in racing off-road, on-road and virtually (opens in new tab), to date his only significant achievement has been winning the National Single-Speed Cross-Country Mountain Bike Championships in 2019.


Height: 177cm

Weight: 67–69kg