What began as a special request by Jens Voigt, who needed something with less drag to help propel him to a new hour record, has since developed into a full-fledged aerodynamic road helmet. The new aero helmet is named the Ballista which derives its name from the ancient Greek weaponry designed to hurl projectiles a great distance – in this case, launch Trek Riders out in front of the peloton. The main ideas behind the new helmet were Fast, Cool and Light.
Bontrager achieved the ‘Fast’ part by starting with a Computer Fluid Dynamic (CFD) project that allowed Bontrager to narrow the design down to a mid-length helmet with 3 large vents at the front of the helmet. Once the final shape of the new helmet was approved, Bontrager took the helmet to the slow-speed wind tunnel in San Diego. Bontrager’s testing determined that the helmet is 48 grams faster than the Specialized Evade and 58 grams faster than the Giro Air Attack helmets.
Bontrager developed a model head that could be heated which in turn allowed Bontrager to measure the heat developed by riders. Using this information, Bontrager was to able to create efficient vent shapes and locations to ensure that the helmet was as cool as possible. The end result was a helmet with a large center channel that draws in large amounts of air that is then funneled through internal recessed channels. The vents and channels allow the air to flow through the helmet and exit through large exhaust ports at the rear of the helmet. This is how they achieved the ‘Cool’ part of the new helmet design.
And Bontrager’s new helmet is light, it only weighs 262g. Not as light as the Velocis helmet, but light for an aero cycling helmet.
BikeRadar (see video below) published a new aero road bike helmet review on July 9, 2015. They compared the Bontrager Ballista, Louis Garneau Course, Kask Protone, Specialized S-works Evade, Bell Star Pro , POC Octal Aero, Giro Synthe, Giant Rivet, and the Giro Air Attack. They tested the helmets in the FASTER wind tunnel in Scottsdale, AZ and found the Bontrager Ballista to be best helmet of the bunch based on the following criteria:
Ballista Helmet Features