VOL. 51 ISSUE 38 SEPTEMBER 23, 2014 P53
America to exercise their ingenu-
ity in creating leading edge prod-
ucts that are then made in Asia,
so as to make them more afford-
able.
That's also true for Zero's high
efficiency brushless Z-Force mo-
tor created in-house by their Ca-
nadian designer, Ryan Biffard,
but again made in China via Wis-
consin-based Motenergy. This
is a radial flux sealed design,
whereby the permanent magnets
are located on the single moving
part, the rotor, while the com-
ponents that get the hottest (the
windings, aka coils) are mounted
on its periphery. Then the heat
can be dissipated via a circular
aluminum housing with deep, ir-
regular finning.
This means there's no bulky,
heavy liquid cooling, since the
motor is passively air-cooled,
meaning there's no fan, although
the Zero S/SR and Zero DS now
feature an aerodynamic chin fair-
ing that funnels air into the motor
to provide additional cooling.
The Zero SR's much larger
controller means that it offers
56 percent more torque and 24
percent more power over the
standard Zero S, and the result
is a genuine E-sportbike able to
cover 0 to 60 mph in a claimed
3.30 seconds with a claimed top
speed of 102 mph.
It also has greater range via a
2.8kWh Z-Force Power Tank fit-
ted as stock (an option on the
2014 Zero S or DS model at a cost
of $2495). This gives an extra 34
miles of range, delivering a total of
171 miles of urban mileage per full
charge as per the EPA's City Duty
Cycle measurement, allowing for
running at a sustained 70 mph for
50 percent of the time.
"The larger 660amp controller
allowed us to raise peak torque
from 68lb/ft to 106lb/ft - a huge
difference, because torque is
directly related to current," says
Zero's CTO Abe Askenazi. "From
a power standpoint, for 2014
we've gone from 40kW to 50kW,
or 54bhp to 67bhp."
Also new for 2014 from Zero is
a five-year/100,000-mile power-
pack warranty covering the motor
and controller on all its models.
The aluminum twin-spar frame
(Above) The SR gets an uprated
43mm Fastace fork that's now fully
adjustable. (Top right) The face of
the SR. (Bottom right) The dash is
also improved – and it now gets a
clock.
