Here is a comparison of the different electric bike motor systems to help you determine which configuration is best for your riding needs.
In the next three postings your will find the pros and cons of each system: the hub motors (front and rear), the crank motor and the rocket drive!
First of all, let’s take a look at the popular hub motors.
Hub motors are electric motors that are housed inside the hub of either the front or rear wheel.
These used to be the most common motors on an electric bike (although crank motors are becoming most popular today).
There are direct drive hub motors that use the whole hub shell as the electric motor. And there are geared hub motors that have a smaller internal motor with planetary gears that drive the hub shell. Here is a comparison of direct drive and geared hub motors.
Here is an overview of front hub, rear hub, and all-in-one hub motors with their pros & cons.
Front Hub Motors
In general a front hub motor pulls you and it creates an all wheel drive e-bike.
• It creates an all wheel drive bike because the motor drives the front wheel and you can power the rear wheel with your pedal power. This can be advantageous for riding in snow or in sand. Some fat e-bikes are coming with front hub motors to create this all wheel drive system.
• Any type of bike drivetrain (gears) can be used: traditional gears with cogs, chain and derailleurs or internal geared hubs (IGH) with a chain or belt drive.
• Front hub motor systems are easy to install or remove from the bike because there are no gear systems to deal with (chain, derailleur, etc.) when compared to a rear hub motor. This is handy for fixing a flat tire or adding/removing electric assist from a conventional bike.
• Front hub motors can provide for a more balanced bike weight distribution if the battery is mounted in the middle or back part of the bike. This helps when lifting the bike onto a car rack or carrying the bike up stairs.
• Some riders do not like the feeling of being “pulled” by the motor.
• Since there is much less weight over the front wheel there is a tendency for the wheel to spin when accelerating on roads that have a layer of loose material (dirt, sand, snow, etc.) or when climbing a steep hill. This is more noticeable on the powerful and torquey front hub motors. I have found that after some time spent riding a front hub motor, you get used to this characteristic and adjust the assist and/or place more weight over the front wheel to work with these conditions.
• Front hub motors generally have a throttle and/or a cadence sensor pedal assist. It is rare to find a torque sensor based pedal assist system for a front hub motor.
• The front hub motors generally are focused on the lower power range (250 watts to 350 watts). There are higher powered front hub motors but they are not as common because the front fork of the bike does not provide as much of structural platform when compared the frame of the bike (rear hub motors).
• Front hub motors generally need a sturdy fork, especially for the higher powered motors. This is very important if you are installing a front hub motor kit on a conventional bike. Check with the kit company for their recommendations on what is required for the front fork. If you are buying a complete e-bike with a front hub motor, then the company selling the complete e-bike has most likely done their homework and supplied an adequate front fork to handle the motor’s power.
• They have a tendency to “bog down” on long steep climbs. See mid drive motors for climbing long and steep hills.
• The higher torque hub motors (generally the more powerful) need larger spokes and sturdy rims.
Next posting we will be talking about Rear Hub Motors….