"I've dreamed of the fastest [bike] helmet ever," says industrial designer Ash Lewin.

Lewin recently got to achieve that dream: He works for San-Francisco-based Giro Sport Design, which unveiled their new Aerohead II helmet at this week's time trials for the Tirreno-Adriatico cycling race in Italy.

"It was incredible to work for months and months on Aerohead II, gathering data and measurements from the team, pushing right to the limits of UCI* regulations. To finally be able to go to the wind tunnel in Eindhoven, put one on Jonas, and see the numbers that proved we'd succeeded was truly special. And of course, then we pushed the design even further, because that's what Giro does."

(*Union Cycliste Internationale, the global governing body for competitive cycling.)

The Jonas that Lewin is referring to is Danish rider and two-time Tour de France winner Jonas Vingegaard, who rides for Holland's Team Visma / Lease a Bike, which collaborated on the design. "We tested the helmet extensively last winter," says Mathieu Heijboer, the team's Head of Performance. "We did this using position scans and 3D printed models of several riders, including Jonas Vingegaard and Wout van Aert, among others."

The unusually-shaped helmet is designed to maximize aerodynamic efficiency while the rider is sitting in the "aero" position. Lewin's challenge was to increase the rider's visibility, achieved by increasing the size of the visor over the helmet's previous iteration. The windbreaking point at the front of the helmet transitions into flares on either side that terminate at the rider's shoulderblades, in an effort to turn both the helmet and rider's torso into a single aerodynamic shape.

It's hard to get a sense of the scale of the helmet in still photos. Giving you a slightly better look on video, here's Paul Martens, Team Visma / Lease a Bike's Head of Apparel, holding up the Aerohead II and describing it: