The Gospel According to Arai: the prime objective of a helmet is impact energy management; everything else is secondary.
Kinetic energy, the amount of work required to accelerate an object from rest to a particular velocity, increases at the square of speed. When speed doubles, say from 30 mph to 60 mph, kinetic energy quadruples. And when an object—such as a motorcycle helmet with your head inside—slows down or stops suddenly, all that kinetic energy has to go somewhere.
To absorb and dissipate kinetic energy upon impact, Arai uses a tough, deformation-resistant aerospace fiberglass shell with a soft, single-piece, multi-density EPS liner. Inspired by the inherently strong shape of an egg, Arai helmets have a smooth, round shell, which slides more easily on the ground and glances off obstacles with less rotational force. And the external vents and face-shield sidepods are designed to break away easily—a frustrating inconvenience should you drop your helmet in a parking lot, but a potential lifesaver should it end up sliding along the ground during a crash.
With a name and look aimed at urban riders, Arai’s new Defiant full-face helmet has an intermediate-oval interior head shape and some features found on other Arai helmets, such as the Hyper-Ridge reinforcing band around the base that strengthens the shell and lowers the center of gravity for less fatigue; the SAI MAX-Vision Brow Vent face shield with a clear Pinlock anti-fog insert; the FCS (Facial Contour Support) cheek pad design that cradles the face, reduces interior noise and makes it easier to put on and take off the helmet; 5mm peel-away temple and cheek pads to customize fit; and a removable/replaceable/washable comfort liner.
Other than styling, what most distinguishes the Defiant from other Arai helmets is its new ventilation system. With partial and fully open positions, the new IR chin vent brings in more fresh air than any full-face helmet I’ve ever worn. New IC-4 upper intake and ACR-4 exhaust vents have slide gates that offer partial and fully open positions, as well as a more complete seal when closed. Brow vent ducting has been redesigned to flow more air past the temples and ear pockets. And the new IR Neck Roll pad has been reshaped for better airflow and to reduce contact and pressure on the ears when donning and doffing the helmet. When it comes to keeping your head cool on a hot day, the Defiant is hard to beat.
New front spoiler edge trim and a pull-down chin spoiler are designed to improve aerodynamics and reduce wind noise, working in conjunction with the flared bottom edge trim to minimize turbulence between the rider’s shoulders and the bottom of the helmet. Comfort has been enhanced with the use of water-repellent Dry-Max material on the cheek pads and neck roll, keeping them from soaking up sweat like a sponge. The rest of the comfort liner uses Dry-Cool material to help dissipate heat.
The new Defiant meets or exceeds DOT and Snell standards, offers exceptional comfort and ventilation, and is very quiet and aerodynamic. But at 62 ounces for a size medium, it’s rather heavy. Pricing ranges from $619.95-$629.95 for solids to $749.95 for graphics. Available sizes are XS-3XL.
For more information, see your dealer or visit araiamericas.com
(This Gear Lab review was published in the August 2013 issue of Rider magazine.)