Section 5 Electric Bikes - haibike XDURO Owner's Manual

Electric Bikes
42
Electric bike components
Motors
Electric bicycles can be built with various
types of motors, which differ in strength,
efficiency, rotational speed, mounting loca-
tion, and other factors.
Electric motors are generally mounted
on bicycles in one of 3 locations: the front
wheel, the rear wheel, or centrally on the
seat tube or around the bottom bracket.
Hub motors
Most wheel-mounted motors are hub-
type motors. These motors sit in the center
of the front or rear wheel, and drive that
wheel directly. The hub motor's axle is held
fixed in either the front or rear dropouts,
and its shell is spun by internal electronics.
The rotation of a hub motor is independent
of any bicycle drivetrain components, like
the cranks, derailleur, or cassette.
Most electric bikes use rear hub motors,
meaning the motor is contained in the rear
wheel. This configuration usually gives the
best handling characteristics, which means
the bike is easier to control; in some cases,
however, a front hub motor is preferable
for a given application.
Hub motors are further classified by
whether they are gearless (direct drive),
or geared. Geared motors are built with
internal planetary reduction gearing. They
give high torque at low speeds, and free-
wheel without any drag. Gearless motors
generally reach higher speeds than geared
Section 5
Electric Bikes
motors, are quieter (some are completely
silent), can be rated for higher wattage, and
are capable of regenerative braking (see
"Does it charge the battery when I pedal?"
on page 43). They also produce less
torque, especially at low speed, and have
some inherent drag when freewheeling.
Center drive motors
Centrally mounted motors which add
power to the bike's normal drivetrain by
driving the chainwheel are growing in popu-
larity. These "center drive" systems are ideal
for off-road applications because of their
high torque, as well as other factors. For
example, in full-suspension bikes, a cen-
ter drive motor greatly reduces unsprung
weight when compared to a hub motor.
Because they integrate with the bicy-
cle's standard drivetrain, center drive
motors usually require more interaction
from the rider than a hub motor does. The
rider must shift the bicycle's chain into the
proper position for a given situation: high
gear for speed, low gear for torque. This
extra effort is paid back by a system that
is able to excel in a wide variety of terrains.
Motor power
Electric bike motors are generally clas-
sified by wattage and torque. Watts are a
measurement of the capacity of the motor
to do work. A motor that is consuming
more watts feels more powerful and usu-
ally reaches higher speeds, but drains the
battery faster. Torque is measured in New-
ton-meters and is a measurement of the
rotating force produced by the motor. This
Electric bike components
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