This video is by Court Rye of ElectricBikeReview.com who is in no way affiliated with ElectricBikeCity.com besides being an awesome purveyor of e-bike information and guidance. Check out his YouTube channel.
Main Types of E-bikes and Their Functions
There are three main types of e-bikes, ones that come with pedal assist and throttle control (most common), those that come with only the pedal assist function, and those that come with only throttle control.
Pedal assist only e-bikes are mostly found in Europe and throttle only e-bikes are mostly found on certain off-road models like the Quiet Kat Fat Kat Fat Tire Electric Bikes.
So, being that most models you will be shopping for will contain a combination of both pedal assist and throttle functions, you should understand the difference between different qualities of pedal assist functions.
Different types of e-bike motors and their sensors
First, I'll remind you of the different types of electric bike motors. There are two main types, the rear hub motor, and the mid-motor. Some e-bikes come with front hub motors as well but they can prove to be more difficult to steer since there is more weight in the front, so more models come in the rear hub motor style.
Rear hub motors and chainring sensors
On rear hub motor e-bike models, there are small magnets mounted to the chain ring of the bicycle (the round thing by your feet that moves the chain when you pedal). These magnets go by a sensor that is mounted to the frame of the bicycle near the chainring and the sensor is connected to the controller. When you start pedaling, the magnets go by the sensor, triggering the sensor to send close an electrical circuit and which tells the controller to send electricity from the battery to the motor and through to the computer if the e-bike has one. This is when you start moving!
Mid-motor e-bikes and internal sensors
On a mid-motor mount e-bike, it usually works a little different, depending on the motor type. Some mid-motors (the less expensive types) are externally mounted and actually have the same magnet sensor system as the rear hub motors. Most of our mid-motor mounted e-bikes don't have this system as many brands have now upgraded to the enclosed mid-motors. This saves wear and tear and protects them from damage during off-roading. The only difference in the sensor systems in these enclosed mid-motors is that they often come with a torque sensor as well as a cadence sensor.
Torque sensors vs. Cadence sensors
A torque sensor tells the controller to only send as much energy from the battery to the motor as is needed according to how hard you are pedaling. This makes the usage of energy much more efficient and often safer because you don't get a huge jolt of speed when you don't want it.
A cadence sensor is less expensive and thus more common. They simply detect how fast the chainring magnets are moving past the magnet sensor and they start putting out an amount of energy equal to the cadence (number of rotations). Cadence sensors are best for city or long distance e-bike riding since you won't need a lot of small torque-related adjustments to the amount of energy outputted, but instead a steady stream of energy that is in direct relation to your median speed.
I hope all this made sense to you! If you have any questions about the particular e-bike you're interested in, please let us know in the comments below or by calling and speaking to our e-bike specialists.
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