This article originally appeared on BikeRadar
With its high profile appearance on the heads of some Team Sky riders just before the 2014 Tour de France, Kask's Protone immediately became both interesting and desirable. Its very rounded shape looks slippery with no protruding ridges or peaks, just subtly sculpted curves that flow between the vents.
- Highs: Fit, ventilation and comfort
- Lows: Such quality doesn't come cheap
From the front it looks like a conventional road helmet, while the rear resembles a road aero lid, with covered upper section and rounded tail.
Its skull-hugging compact profile is the result of computational fluid dynamics (CFD) design and wind tunnel testing, and it's certainly less bulky than some, though still has a complete Multi In Moulded polycarbonate shell covering the reinforced EPS core.
The diminutive dimensions belie its spaciousness. Our 251g medium fitted well, even with a skull cap, when we'd usually wear large. The Octo Fit retention system offers a huge adjustment range, the occipital pads moving vertically and laterally, and a rotary dial tightens a headband that doesn't foul your glasses. Achieving a perfect fit is simple, and the comfy eco leather chinstrap keeps everything secure.
Internally, the 5mm-thick 3D Dry multilayer open cell padding is antimicrobial treated, and perforated to reduce skin contact, with a CoolMax pad at the front. It all wicks sweat effectively, but even on hot days is superbly ventilated by the phenomenal airflow drawn through the eight forward facing vents; no subtle, compromised waft, but several jets of air channelled evenly across the head to six large exit ports.
The Protone was designed to maintain aerodynamics and airflow in any common riding position, and however you move your head, it remains consistent. We can't verify aero performance, but with many helmets, dipping or turning your head creates an obvious increase in wind noise, whereas the Protone is incredibly quiet and unobtrusive, and just feels fast.