A typical hub motor system on an electric bicycle
Regular bicycles provide users with a form of human-powered transportation that is much more efficient and faster than walking. However, they leave something to be desired when it comes to top speed and hill-climbing power.
Adding the assistance of an electric motor allows you to still pedal as much as desired, but adds as much as 20 mph to your top speed. In addition, the motor will help you accelerate from a stop and climb up steep grades.
Relatively inexpensive conversion kits are available from a number of retailers, and most can be installed in a few hours.
Instructions
1. Obtain a suitable bicycle for conversion. The frame should be thick and strong, and the bicycle should have solid parts which are in good condition. Bikes with shock absorbers on the front fork are unsuitable for conversion, and should not be fitted with a motor. Most kits work with wheels between 20 and 26 inches in diameter. The bike chosen for this job should have exceptionally strong brakes, since it will be traveling at a much higher speed than it was designed for.
2. Purchase a conversion kit. Numerous Internet stores (see the Additional Resources section) stock these kits, and they are all over eBay. They are relatively inexpensive, at around $350 to $650 on a starter level. Motors may vary greatly in power. Higher voltage systems have lots of torque, move faster, and reach top speed quicker--but drain the batteries much more rapidly than lower voltage motors do. Your daily commute range should be taken into account when selecting a conversion kit to ensure you wind up with one that fits your individual needs.
3. Mount the motor on the bicycle. Follow the manufacturer's instructions, since all systems are different. With a hub motor, you will begin by removing your existing wheel, and replacing it with one that has the motor built in. Other systems may have an external motor that mounts away from the wheel, and sends power to it through a drive chain. The battery (or batteries) will need to be mounted to the frame of the bike, or behind the seat, and secured into position.
4. Run the wiring from the motor, to the controller (if applicable), to the throttle on the handlebars. Ensure that all of the cords are located outside the path of any moving parts, and that they will not interfere with any of the bicycle's natural movements. Remember, the power wires will be carrying high-amperage electricity, and could potentially be dangerous if installed incorrectly.
5. Charge the batteries, then take the new bike out for a spin. While on the test drive, don't go too fast until you are confident the system is installed and functioning correctly. Pedaling away from a stop, then waiting until some momentum is gathered to engage the motor is the proper way to take off. Accelerating from a dead stop puts unneeded stress on the motor, and drains the battery much faster than normal. Look out for any weird noises or occurrences that might signal a potential problem.
6. Make any modifications that are required. Bigger disk brakes may be needed to slow the bike down from high speeds. Larger amp-hour capacity batteries can be used to replace the stock ones and boost range and power. Tougher tires may be required, since powered bikes will cause more wear-and-tear than normal usage would. A digital speedometer to measure speed and distance is a helpful addition.
