The technological path from the Wrights’ powered flight in 1903 to Neil Armstrong hopping off the ladder onto the powdery surface of the moon in 1969 was anything but easy. It would take to the end of the Wright decade before powered flight was beyond purely experimental and World War I to give developers impetus and money to make the airplane practical. It was an often tortured and controversial road from Kill Devil Hills to the Sea of Tranquility.
It’s much the same deal with electric motorcycles. Pushed ahead by the specter of ever-rising gas prices and drawn by important developments in battery and motor technology, electric bikes represent an opportunity for two-wheel growth and a greener image. Yet the product remains in its infancy. We’re at about the Glenn Curtiss/June Bug point in the timeline.
The 2012 Zero S packs significant improvements over the last Zero we tested in 2010, ushering in such upgrades as a toothed-belt direct drive (to replace the previous, much noisier chain); and a new brushless, permanent-magnet AC motor that has a higher maximum rpm (6300 vs. 3350) is said to provide smoother response and promises no maintenance compared to the previous brush-type motor.
Styling alterations make the S and DS (its dual-sporty stablemate) look more like genuine small motorcycles and less like the shotgun marriage of a mountain bike and an electric golf cart. Some of that new styling, hung upon a familiar perimeter frame with a full cradle, is there to hide and help cool the big upgrade for 2012: a 9-kilowatt-hour battery pack. Two packs are offered for S and DS this year, a 6 kW-h and the 9. They make up the whole difference in price, and there is a 44-pound weight penalty for the larger battery. The 6 kW-h S is $11,495; $2500 more gets you the big pack, which provides no more acceleration but boosts range.
On our dyno, the direct-drive, clutchless Zero’s air-cooled motor put 25.7 horsepower to the rear wheel in the Sport mode and 3.4 fewer in the fun-sapping (but longer-range) Eco mode. Torque in Sport is just over 40 foot-pounds from about 10 mph to 60, just below 30 ft.-lb. over that same speed range in Eco. By comparison, a Honda CBR250R makes 23.7 hp and 12.7 ft.-lb. and a Kawasaki Ninja 250R makes 25.5/13.5.
Despite the decent peak numbers on the Zero, sometimes it feels like less. “In power terms, my single greatest complaint is that the Zero launches so gently,” says EIC Mark Hoyer, who also spent time on the Zero S in 2010. “It is very soft off the line and really doesn’t give you a strong sense of acceleration until you get past 35. Then it drives great through the next 40 mph.”
In Sport mode, the Zero unleashes a bit more power but the response remains aggravatingly gentle. Explains Zero’s chief technical officer, Abe Askenazi (ex-Buell), “Even though we are delivering near-constant torque to the rear wheel from 3 to 60 mph, the off-the-line sensation is not as strong as on an internal-combustion-engine bike with a very low first gear. Since most of the acceleration events in people’s rides take place within mid-to-high speeds, we do believe that the extensive benefits of not carrying around a transmission far outweigh the limited benefits of doing so.” Seasoned motorcycle riders will chafe at the lazy throttle response while the fresh-from-the-MSF types will find it comforting.
With a quarter-mile time of 17.64 seconds at 76.96 mph (add almost 3 seconds to that in Eco mode), the Zero trails the aforementioned CBR250R (16.15 sec. at 77 mph) and Ninja 250 (15.62 at 81). Top speed is 84 mph, 3 mph slower than the CBR and 9 mph under the Ninja. Before you scoff, consider that the top-gear roll-on for the Ninja in our full test (June, 2008) was 7.5 seconds 40-60 mph and 9.3 for 60-80. The single-speed
Zero exercises its advantage in the 40-60 range by being in its torque sweet spot, ripping off a 3.4-second time, just a tenth slower than the 191.7-hp Kawasaki ZX-14R. It takes 10.5 seconds to do the 60-80 run, by which time the 14R has broken the sound barrier…
While we poke fun at some aspects of the Zero’s straight-line performance, bear in mind that it’s a whole lot quicker and faster than the previous model and handily beats the Brammo Enertia we tested in April, 2010. Further, it genuinely feels quick once it’s allowed to be on its electric pipe, so to speak. Running between 30 and 70 mph is fun, it’s easy to pass in normal traffic and the bike rides like a “real” motorcycle. Just a whole lot quieter and smoother.