The rate of progress at Zero Motorcycles has accelerated for 2013. A new motor offers twice as much power as last year’s Zeros, and new battery packs boost range at highway speeds by more than 25 percent. If things continue at this rate, the company will be offering electric motorcycles in a couple of years that exceed the performance of internal combustion-powered bikes in almost every way. While the curve is more likely to level off in the short term (Zero’s engineers have to sleep sometime, and battery technology remains a limiter), what has been achieved is nothing short of amazing.
A brief ride on the new FX model and the S tells the story: The FX is essentially a street-legal version of the 2013 MX model dipped in flat black paint and fitted with Zero’s torquiest motor. With 44-horsepower, 70 pound-feet of torque and 85-mph gearing, the FX pulls quickly away from a stop with its 21-inch front tire in just light contact with the ground. It feels light, small, and aggressive. Weighing in at just 275 pounds with a 5.7 kWh battery, the FX is the hooligan machine in Zero’s line.
The heavily revised S model gets the 54-horsepower version of the new motor, and either an 8.5 or 11.4 kWh battery pack. Geared for 95 mph and weighing 350 pounds with the smaller pack (382 with the larger), it doesn’t launch as hard as the FX, but still accelerates from a stop far harder than last year’s S model. But its midrange is what’s amazing; a flat torque curve pushes the S from 30 to 75 mph with that constant linear acceleration feel produced almost exclusively by turbocharged engines in the gasoline world. Roll-on performance is more open-class than middleweight.
All of Zero’s 2013 models receive a version of the company’s new electric motor, an innovative, sealed, radial-flux, permanent-magnet motor unique in its simplicity. Designed for direct drive, the motor puts its most heat-sensitive and hottest components (coils) on its periphery, where the heat can be dissipated via an aluminum housing with deep finning. There is no fan or any other cooling. (Grants from California helped pay for its development.)
New Nissin brakes produce hard stops with light brake lever effort, while the belt drive and direct drive motor help create a machine with less operating noise than a bicycle with a derailleur. The motor’s greater high-speed efficiency improves range, according to Zero, with the S capable of traveling 64 or 85 miles at 55 mph, depending on pack size. On a low-speed urban cycle, the range numbers expand to 103 or 137 miles, respectively.
The MX model has been redesigned into a full-size bike, and gets the full 54 horsepower version of the motor, along with much requested 18- and 21-inch wheels. Like all other Zeros, it also receives new battery packs for 2013, in this case either one or two plug-in 2.8 kWh modules. It is available with and will run on a single module, with the same low-end power and torque, but with the torque falling at higher rpm so that only half as much top-end power is produced. Plug in a second 42-pound pack, and power jumps to the full 54 horses while machine weight increases to 265 pounds. Extra packs are available, and can be swapped at the track in less than a minute.
In other notable changes, both the S and DS models get passenger accommodations and quicker battery charging. The XU remains the most affordable and smallest machine, with a version of the new motor and the same batteries as the MX and FX. Prices range from $7,995 for the 2.8 kWh XU to $15,995 for the 11.4 kWh versions of the S and DS.