## Electric Bike Parts and Jargon

In this article, we break down some terms that are often misunderstood when talking about electric bikes parts.

Voltage

Voltage can be tricky to explain, the easiest way to understand it is to think of it as the pressure and strength of the power source (think of it as water pressure in a hose). Generally speaking, the higher the voltage, the better. This is because the high voltage is passed more efficiently through the wires and motor. Typically e-bikes run between 12-36 volts, with 12 volts usually being the lowest you can find as anything below that will require overtime to get the bike to the same speed. On more powerful motors, the e-bike voltage will increase to around 36 volts.

ampere

AMP measures the volume or amount of available electrical current. To complement this definition, flow in amperes is called current. The speed at which the current flows is fixed and does not change. The higher the amperage level in the system, the thicker the wiring you will need to accommodate the power level.

watt

Wattage is considered the “power” of a system and is calculated by multiplying the flow in amperes (current) and voltage (pressure). Most people look at motor power and battery capacity (voltage) to determine e-bike performance, but the number of watt-hours in the system is what matters. This is an important determinant of the level of power output available to the system and how far it can go on a single charge.

How many watts do I need?

This will depend on the type of riding you will be doing and how much you will be using the motor. Generally, an e-bike intended for mountain use will require more wattage than one intended strictly for use on flat terrain. If you want the motor to be used in hilly areas, you’ll probably want a motor with a peak power draw of around 600 watts or more. For flat terrain, a 200W motor may be sufficient.

How big should my battery be?

Battery capacity is usually measured by the amount of current (Amps/hour) it can supply over a period of time. However, to get the most accurate reading, you’ll need to multiply that number by the voltage to get watts/hour. Capacity readings on batteries are indicative only, as performance may vary depending on usage conditions (temperature, battery age, etc.). If you will be using your e-bike regularly and driving longer distances, you should look for a battery with a higher capacity.

gear hub

When the hub is mentioned in the context of an e-bike, it usually means the motor. There are several different types of motors, and we’ve found that geared hubs are the most popular and efficient. This motor works by integrating the motor in the center of the rear wheel and using a gear and chain to drive it.

direct drive hub

Unlike gear hubs, where all the components of a gear hub are contained within the motor housing, direct drive motors use the housing as part of the motor. The housing usually houses extremely strong rare earth magnets that allow the motor to run. When the motor is running, it directly drives the wheels, hence the name direct drive. In such a drive system, the wheel itself becomes the motor, which simply rotates around a central axis that serves as the rear axle. Typically, direct drive motors need to be large and heavy to produce the same level of power as a geared motor of equivalent power.

performance appraisal system

Stands for Pedal Assist. It is the most common drive system on e-bikes. You’ll sometimes find pure pedal assist (European) and almost never pure throttle. PAS allows riders to choose how much energy they want to use and how much battery power they want to use. Typically, e-bikes have 5 levels of pedal assist.

sprocket

A sprocket is a simple metal disc found in the gear system of an electric bicycle. They have teeth protruding from the outer edge that mesh with the links in the chain. There is one sprocket for each gear mounted on the rear wheel, usually one on the pedal crank.

spoke

Spokes are what support the wheels of your bicycle. They are pieces of metal that run from the hub to the outer rim. In general, the more spokes you have on a wheel, the stronger the wheel because any force applied to the wheel will be shared by each spoke. Retrofitting can be tricky if you happen to break a spoke, and if this happens we recommend taking your e-bike to a professional for inspection.