​Which is the Best Ebike Motor: Hub or Mid-Drive?

If you are interested in purchasing an ebike and researching the options, you probably discovered there are two types of motors on modern ebikes: the hub and the mid drive.  Besides your budget, where the motor is located is the biggest decision you will have to make.  While both options will provide you with assistance when you pedal, there are big differences in the technology and it is helpful to understand what these are before you commit.  

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Hub
A Hub motor is placed on the center or hub of the rear wheel, although placing the motor on the hub of the front wheel is also possible.  The motor provides propulsion by spinning the tire on which it is mounted.  The motor has no impact on the main pedal drive system.
 
There are two types of hub motors.  Geared hub motors have internal planetary gears to reduce the speed of the higher RPM motor.  The gears are a point of weakness since a tooth can break off and the reinforced nylon gears will eventually strip. 
 
Gearless have no gearing and directly connect the lower RPM motor stator’s axle to the bike.   There are no moving parts aside from their bearings so nothing to wear out. ​

Pros for Hub Drive

• Simple and inexpensive to manufacture based on designs over a decade old resulting in low cost
• Can be retrofitted to almost any traditional bicycle using a conversion kit
• Offers redundancy with the pedal drive system so if you lose one you can get home on the other, i.e. if a chain breaks you can ride home on the electric power (if you have a throttle) or if the hub motor fails, you can pedal back home

 
Cons for Hub Drive

• Limited options for wheel components such as rims, tires, and rear cassettes (which are often limited to 7 speeds)
• Repairing a flat tire or fixing a bent or broken rim or spoke is a lengthy procedure because you have to disconnect the motor wire or manipulate the heavy wheel while it is still tethered to the bike
• Does not maneuver naturally, i.e. feels like it is being pushed or pulled along
• Additional weight in a rear hub motor makes it harder to balance
• A front hub motor makes the bike harder to steer and stop and the additional weight on a fork not designed for a hub motor can result in damage over time 
• Spins slow on a steep hill so if a lot of help is requested, motor might overheat leading to a temporary shut-off or damage to the magnets inside
• A conversion kit applied to a regular bike may be a safety concern since the bike was not designed for the additional weight, strain, and speed on the bike’s frame, chain, gears and brakes
• Relies on cadence sensors for pedal assist which regulates motor speed based on pedal speed resulting in jerky or awkward motor timing
• A wheel with a hub motor is easier to steal than a motor in the frame.
• Shifting gears while using the throttle and extra stress from the torque can break the chain when it is between cogs
• Heavier than mid-drives

Mid-Drive
A mid drive motor is located in the middle of the bike in between the pedals at the bike’s bottom bracket and is designed to drive the cranks or pedals and transfer the motor’s power to the rear wheel via the chain drive.   Advancements in mid-drive motor technology is resulting in smaller, lighter, and quieter ebikes.  

Pros for Mid Drive

• Higher performance and torque compared with a similarly powered hub motor
• Location takes advantage of the bike’s existing gears delivering more power and range
• Maintenance and service of the motor is as easy as taking out two bolts and replacing it
• Better weight distribution by positioning the motor in the bike’s center
• Wheels can be removed to repair a flat like a regular bike without affecting the motor and there is the freedom to use any wheel, tire, and cassette that you wish.
• Smaller and lighter than a hub motor of similar power.
• Torque sensors used to regulate the motor power based on how hard you push on the pedals results in a smoother ride

 
Cons for Mid Drive

• Requires a specially designed bike frame built around the motor
• Hard on the bike’s drive system due to the continuous higher output of power on the drive chain than can be produced by a human
• More points of failure in the mid-drive motor since it has more moving parts
• More expensive than hub motors

 
So which is best?  There are advantages and disadvantages of each based on cost, weight, gear usage, and reliability.  So unless you have some unique requirements for each of these key attributes, just make your selection and get outside and enjoy your ride!  ​​

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