E-bike products and scooters Cycling Without that Pesky Peddling | Page 12

Power Assist
The idea behind this mode is that the rider will do the pedaling as they do on a traditional bike but can call
upon assistance when they get tired or are struggling up a hill. This type of electric bicycle is quite different
from the standard full-power version we have discussed so far. Power assisted bicycles do not have hub
motors fixed to the wheels instead they have a different type of motor that sits beside and drives the rear
gear sprocket or in some cases it drives a fly-wheel that rubs against the tyre providing the additional
propulsion. The difference is that this type of electric motor has very low resistance to being spun without
any power applied for example when pedaled. This is unlike a full power hub motor that is near impossible
to turn manually without any applied power as you are effectively changing it from a motor into a
generator. This means that as you are only applying power as needed to assist your efforts the range
increases dramatically to around 50 -100 miles dependent on use. Also because they do not use fixed motor
hubs there are kits available that can convert a traditional bicycle in a power assisted electric bicycle.
Typically a basic conversion kit comprises of a bolt-on DC electric motor which goes just above the back
wheel, which presses against the tyre driving it forward by friction alone. The motor gets its power from a
compact battery that clips onto the frame. This kit may add quite bit of weight to the bike as the motor is
around 3kg and the battery maybe as much as 6kg, but it does give you extra range and speed when
required.