Traditionally, aerodynamic cycling helmets have relied on sloping shapes, minimal venting, and a teardrop tail design to dictate the flow of air in order to overcome aerodynamic drag. However, with Giro's new Air Attack Shield, its engineers had to rethink the shape of this typical design. The reason for this was simple -- the objective of the Air Attack was to mate an aerodynamic helmet with a design that was compact, well-ventilated, and able to be worn for long periods of time.
To start, the helmet was designed with a similar frontal area as Giro's Selector time trial helmet, only with a new 'chopped-off' rear section. Wind tunnel testing proved that the air still 'thinks' it's moving around a long tail, when, in fact, the excess material no longer exists. In addition to now having roughly the same minimal drag (only 11% more) than the Selector, the Air Attack provides a drastic increase in weight savings. In fact, the claimed weight of the Air Attack (without the shield attached) is 264g versus the Selector's 430g.
The second major consideration when designing the Air Attack came down to thermodynamics. After all, Giro's engineers knew that a lightweight, aerodynamic helmet was worthless to the peloton if didn't ventilate well. This led Giro to the development of what it calls 'the Therminator,' which is a head-form heated to the temperature of a human, with 'thermo-couples' added on the outside. The information relayed from this system allowed engineers to map out parts of the head that stayed both cool and warm in the wind tunnel, which let Giro locate where vents were working and where they were not. What Giro found was that as air hits the rider, there is a very high pressure zone right at the forehead. In response, the Air Attack's new fit system, known as Roc Loc Air, suspends the rider's head off of the EPS, allowing air entered in that front three millimeter portion of the helmet to flow over the top of the head and out the large, strategically placed back channels. Remember that 11% additional drag over the Selector? The 28% increased cooling power achieved ought to make up for it.
As for the shield itself, Giro collaborated with Zeiss Optics in order to create the polycarbonate design. This partnership developed into a broad lens with high-levels of both durability and clarity. In fact, Giro argues that the shield provides a wider field of coverage and view, given that it's free from any framing. And this brings us to our next topic, the shield's attachment. Essentially, the shield is held by three magnets at the front of the helmet. This system of attachment allows you to spin the shield around, up and out of the way. You'll notice that the field docks automatically, and creates a streamlined frontal surface with the Air Attack helmet.
The Attack isn't as light as Giro's fully-vented and top-end Aeon helmet, but it still provides you with 97% of its cooling efficiency and an 11% boost in aerodynamic efficiency. We'll let you weigh the trade-off.
The Giro Air Attack Shield Helmet is available in the sizes Small, Medium, and Large and in the colors Black/silver, Black/red, Blue/black, and White/silver
With a removable eye shield and a sleek, compact design informed by wind-tunnel testing, the Giro Air Attack Shield bike helmet is a highly aerodynamic helmet for all-around road riding.
|Head circumference:||20-24.75 inch|
|Suggested Use:||Road, Aero/Tri|
|Giro Air Attack Eye Shield||$20.00|
When Are other shield colors going to be available?
Otherwise, this helmet is the best thing since sliced bread. I've ridden it in hot/dry and hot/humid weather and ventilation is zero problem. Don't know about "aero" but it's far and away the most comfortable helmet I've ever ridden!