Electric Motor for Bicycle Options?

Types of Electric Bike Motors

Mid-Drive Motors

Mid-drive motors are located at the center of the bikes frame usually in between the cranks. Mid-drive motors are less common on electric bikes but they have become more popular in recent years. One of the major advantages of a mid-drive motor over a hub motor is that mid-drive motors use a torque sensor for the pedal assist system. A torque sensor system allows the motor to sense how hard you push on the pedals by measuring the crank. This usually provides a smoother ride on your e-bike. Another advantage of mid-drive motors over hub motors is that they are usually lighter and smaller. Additionally, due to the mid-drive motor being located in the middle part of the frame and not the middle of the wheel, it is much easier to change your tires on a mid-drive motor e-bike. 

Hub-Motors

There are two types of hub motors; geared hub motors and direct-drive hub motors. 

Geared Hub Motors

Geared hub motors are the most common motor you will find on an electric bike. Tower’s electric cruiser bike is equipped with a 500 watt geared hub motor. A geared hub motor consists of a motor shaft, which connects to the planetary gears, which connects to the hub. This series of planetary gears spins the hub to lower the speed of the bike. Unlike a mid-drive motor, a hub motor operates outside of the e-bike chain drive. Because the hub motor operates outside of the drive system, the pedal assist system uses cadence sensors to activate the pedal assist. The advantage of the hub motor being outside the drive system is that it does not create unnecessary wear and tear on the chains and cogs making for less maintenance on the e-bike. Another advantage of being separate from the drive system is that it adds redundancy to the bike. If your chain were to break you can simply use the electric throttle to finish your journey. If the battery runs out, you can simply manually pedal to finish your journey. Geared hub motors also provide more torque than direct drive hub motors but direct drive motors can reach higher speeds. 

There are also two different types of geared hub motors; a front hub and a rear hub. The majority of e-bikes on the market today have rear hub motors. The main advantage of rear hub motors compared to front hub motors are that they provide greater traction and they more securely mount to the frame. Front hub motors can be beneficial because they redistribute the weight better for e-bikes that have a rear-mounted battery. Overall, geared hub motors are generally cheaper than mid-drive motors but provide plenty of advantages for the casual electric bike rider.

Direct-Drive Hub Motor

Direct drive hub motors are the simplest and least common of all electric bike motors. A direct drive motor consists of the motors shaft being fixed in place. The motor spins around the shaft which then propels you forward. One major advantage of direct drive motors is that they have regenerative braking. This means that as you squeeze the brake the braking process actually generates electricity for your bike. Although the energy generated from the braking process is very minimal it can be the difference between making it to your destination or not. One disadvantage of direct drive motors is that they tend to be heavier and larger in diameter than geared hub motors. 

Electric Motor for Bicycle Resources you might find helpful 

Electric Bike Motor Wattage

A watt is a unit of power used to measure the output of an electric bike. The amount of power you need from your e-bike will depend on a variety of factors, most notably your weight and the terrain you are riding. For example, if you only weigh 120lbs and live in a flat city, a 24V 250-Watt ebike should work fine for you. If you are heavier set and live near steep hills then you’ll need something that has a 48V 500 Watt motor. 

Motor output/battery capacity is capped in the USA at 750 watts. Any motors with power greater than this may be subject to tax and motor vehicle regulations. Think of wattage as the size of the gas tank. The measurement of a motor’s output is calculated through the combination of 2 factors: battery AMP hours multiplied by battery voltage. AMPs measure the capacity of the battery and Voltage measures the strength of the electrical source for a given level of current.

Put simply, the more wattage you run through the motor, the faster you’ll go, up to a point. This point is determined by the gearing (how many gears your ebike has, the size of sprockets and the size of the wheels) of the bike as this will ultimately determine what the top speed is.

The Tower Beach Bum has a 500-watt motor that provides it with significant torque and hill climbing ability.  We personally designed our motor for exceptional hill climbing ability. Our torque measures at an astounding 65 NM (Newton Meters) to provide the Beach Bum with the extra juice you need to climb any hill. 

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