Cycle News

2015 ZERO SR, S, DS AND FX FIRST RIDE P54 that intrinsically makes torque anywhere, it's incredibly easy to get off the mark. And thanks to careful attention by Askenazi and his men, the previous brisk initial pickup in Sport mode, because of the extra torque that was remi- niscent of a badly mapped EFI on a combustion engine, is now a thing of the past. So now there's no longer any need to preload the throttle slightly at a standstill while rest- ing your foot on the brake lever, then depart the scene by simply lifting your toes while simultane- ously winding the gas further open. Instead, with no clutch le- ver to pay out progressively for a smooth departure, you just twist your right wrist to gain access to >>GETTING TECHNICAL: MAY THE Z-FORCE BE WITH YOU The man largely re- sponsible for driving the breakneck advance in transportation E-technology that Zero Motorcycles is currently pursuing is Mexi- can engineer Abe Askenazi, leader of the team of 35 R&D technicians at the company's Scotts Valley headquarters. Formerly with Buell Motorcycle Co. for 15 years, winding up as its senior development engineer working alongside Erik Buell, Askenazi was recruited by Zero in 2010, and promoted to the role of CTO/Chief Technology Officer in 2011. He thus led the team that for 2013 delivered the first mass-pro- duced electric motorcycles capable of exceeding 100 miles on a single charge, with Zero's self-built bat- teries now claimed to last up to 415,000 miles, and totally maintenance-free powertrains. Under his lead, Zero's engineers have continued to refine these industry-leading products for 2015. "For this model year our focus was much more on the chassis side of things, to refine the package and deliver a truly premium, well-rounded motorcycle at a competitive price," says Askenazi. "Whereas in the past our focus had been on the electric powertrain, for 2015 we were able to collaborate with some top- end suppliers to provide a complete package that matches the quality of this on the chassis side, too." Zero's highest-perfor- mance model, the SR, is fit- ted with a 56 percent larger capacity 660 amp Sevcon Size Six controller than the Zero S that was developed by Zero, but is made in China. Call it the Apple syn- drome: just like their neigh- bors over the hill in Silicon Valley, Zero employs people in America to exercise their ingenuity in creating leading edge products that are then made in Asia, so as to make them more affordable. Same thing for Zero's brushless AC Z-Force motor weigh- ing 24 pounds and created in-house by their Canadian designer, Ryan Biffard, but again made in China by Broad Ocean, one of the country's major manufac- turers of electric motors. This is a radial flux sealed design, whereby the perma- nent magnets are located on the single moving part, i.e. the rotor, while the compo- nents which get hottest—the windings, aka coils—are mounted on its periphery, whence the heat can be dissipated via a circular alu- minum housing with deep, irregular finning. This means there's no bulky, heavy liquid cooling, since the motor is passively air-cooled, hence there's no fan, although the quite refined styling of the Zero S/SR/DS by in-house designer Matt Bentley does feature an aerodynamic chin fairing that funnels air into the motor to provide additional cooling. The Zero SR's much larger 660 amp controller, which is also air-cooled, means that it offers 56 percent more torque and 24 percent more power over the standard Zero S. "The larger controller has allowed us to raise peak torque from 68 lb-ft [92Nm] to 106 lb-ft [144Nm]—a huge difference, because torque is directly related to cur- rent," says Askenazi. The result is a genuine E-sportbike able to cover 0-60 mph in a claimed 3.30 seconds (3.90 seconds fitted with the heavier Power Tank available as an accessory), with a top speed of 102 mph, which I can confirm having seen on the SR dash's speedo. It also has greater range via the 2.8 kWh Z-Force Power Tank that can be added to any 2015 Zero S or DS model at a cost of $2,495. This gives an extra 34 miles of range, delivering that impressive total of 185 miles urban mileage per full charge as per the EPA's City Duty Cycle measure- ment. Zero continues to offer a five-year/100,000- mile powerpack warranty covering the battery pack on all its models, while the rest of the motorcycle continues to be covered by their two-year, unlimited mileage warranty. The twin-spar cast frame weighing 22 pounds and made by YCM in China from 6061 aircraft grade aluminum is unchanged from before, still wrapping around the battery pack and using the AC motor as a fully stressed component. Head angle is 24º with a tight 3.1 inches of trail and a 55.5-inch wheelbase. But the entire 2015 Zero lineup is now fitted with specially developed Showa suspen- sion replacing the Tai- wanese Fastace package used before, with a 43mm upside down fork offering 6.3 inches of wheel travel and a linkless cantilever rear monoshock giving 6.3

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