Mid-Drive or Hub-Drive Motor?

Posted on 18 November 2021
By David

Mid-Drive or Hub-Drive?

One of the most common questions we are asked is about the difference between Mid-Drive and Hub-Drive electric bike motors. There are 2 types of electric bike motor systems, hub/wheel based systems, and mid mounted/crank based systems. Whilst there are exceptions, a mid drive system is in almost every case a superior way of powering an electric bicycle. The 3 main advantages of a mid-drive system are balance, efficiency, and ease of maintenance.

Balance

For a hub-drive eBike, the motor provides propulsion by spinning the wheel on which it is mounted. Some riders find a hub drive bike does not maneuver naturally; depending on whether the hub motor is on the front or rear wheel, the bike feels like it is being pushed or pulled along. This can create issues for an inexperienced rider, either because the additional weight in the back wheel makes it harder to balance, or because the additional weight in the front creates steering challenges.For a mid-drive eBike, the motor is positioned directly in between the pedals at the bike’s bottom bracket. This ensures a low and central center of gravity, providing load balancing and creating the feeling of riding a traditional bike. Riders don’t feel the additional weight of the motor because of where it is positioned, giving a mid-drive eBike solid balance and stability.

Efficiency

A difference riders can’t see, but will experience on a long ride (especially on hills), is that a bike with a mid-drive motor works synergistically with the bike’s gears for higher efficiency, which translates into longer riding range per charge. Electric motors like to spin fast, not slow. When the rider shifts gears to pedal at a natural bike-riding cadence (50-100 rpm), the motor in between the pedals is churning at an efficient rpm as well.With a hub-drive eBike, the motor drives the wheel, which can spin very slowly on a steep hill. When a motor is spinning slow and the rider is requesting lots of help from the hub motor, it can sometimes overheat, leading to a temporary shut-off (best-case), or permanent damage to the magnets inside (worst-case).

Maintenance

Whilst the motors themselves should be maintenance free, flat tires – a periodic occurrence when riding as often and far as eBikers do - is a quick fix with a mid-drive just like it would be with a regular bike, as the wheels can be taken off without affecting the motor.

With a hub motor, the motor is part of the wheel itself, so even a minor hiccup like a flat tire can turn into a lengthy annoyance. Hub drive wheels are bolted on, meaning you will need to carry a spanner, and because the motor is attached to a battery, you will need to undo a power cable in order to remove the wheel. Replacing a bent or broken rim on a hub-drive eBike can be problematic and expensive, and requires detaching the motor from the rim and re-spoking. Wheels on a mid-drive eBike are the same as those on a non-electric bike.

Motors, or “drive units” come in many different flavours and not all are created equal. Even within the same brand, there are noticeable differences between various models. The best way to compare one motor with the next is to ride them, which is why we encourage our customers to ride several different motors to help understand the differences, and establish any preferences.

Whatever option you choose, it is important to confirm what warranty process and support exists for that product in New Zealand if something does unfortunately go wrong. All our bikes are equipped with mid-drive Bosch, Shimano, or Specialized (Brose) motor systems, and are well supported by large, established local distributors.