When choosing an electric bike conversion kit for your bicycle, you will have two kinds of motors to choose from: a direct drive or geared motor. Available in a wide range of power options- from 250w’s that get up to 15mph to 1000w’s that get up to 28mph- each electric bike conversion kit motor has its benefits and drawbacks, so how and where you plan to ride will determine the right type for you.
Direct Drive Motors
Sometimes referred to as brushless, or “speed motors,” direct drive motor setups tend to be bigger and heavier than their geared counterparts. They require more energy to pick up speed. However, once they get going, they build upon and maintain that speed, giving them the ability to reach higher maximum speeds.
How does it work?
Direct drive motors relatively simple in design, consisting of only two pieces—a stator and a rotor —in which the hub of the bike remains stationary (the stator) and the wheel rim rotates around it (the rotor). Its simple electric motor design incorporates the wheel hub as the axis, and the wheel rim as the outer motor “casing”. Once electricity is fed from the rechargeable battery through the copper-wound stator (axle), it creates an electromagnetic field, to which the magnets installed around the wheel rim react by rotating. This, of course, moves the bicycle forward.
Since the magnets and copper-wound hub aren’t touching each other, and the only moving part consists of the wheel rotating on its axle, the direct drive hub motor makes no more noise than a conventional bicycle coasting down a hill. It has no gears rubbing together as they interlock, making these the quietest motors you can find.
Direct drive motors are not as efficient in stop-and-go traffic, because each startup requires a new surge of energy from the battery, which will die faster if used heavily in this manner. Moreover, the magnetic field these motors have will produce drag when pedaling or coasting, making it slower when not throttled and harder to pedal.
Due to the more substantial weight and greater initial energy use when speeding up, direct drive motors won’t take you quite as far as geared motors on the same fully-charged battery. The range reduction is usually only a couple of miles.
That said, if you live in a flat area or don’t go off-road very often, a direct drive ebike motor may be the better choice for you. If you don’t mind pedaling to help going up a hill, and really want to reach some daredevil-level top speeds, direct drive motors are definitely the way to go! Here are a couple of favorites rated by direct-drive riders: