Electric bikes are one the fastest growing personal transportation vehicles in the market. The background to its popularity is that people are now looking for alternative ways to get around, and due to their convenience, zero-emission, easy-to-use and exceptional pedal assistance technology it is easy to understand why people are drawn to them. The motor electric bike will get you wherever you need to go faster and further than ever before when compared to a normal pushbike.
In the market today, there is a broad range of brands, models, motor sizes and prices to choose from. This might make it hard to understand what to look for when choosing the perfect eBike for you and what type of features you need. Especially when it comes to the bike motor. Like, what is the difference between a mid-drive motor and a hub motor? What bike motor is the best for me?
What is a Hub Motor?
A hub motor is the most common motor to be found on cheaper electric bicycles. The motor is either built into the front or rear wheel - the back wheel being the most common. It is positioned on the hub of the wheel and applies torque directly to the wheel, making the tires spin.
It functions independently from the e-bike’s gears, so instead of adding a motor that is powering the wheels by gears or chain (like mid-drive), the hub motor is positioned directly on the wheel so that the motor and wheel are one and the same.
What is a Mid-drive motor?
The mid-drive motor and gears are integrated into the pedal shaft of the eBike - between the pedals. It transfers power directly to the chain or belt which in turn drives power to the wheel. Meaning it is influenced by the gears. This type of motor is generally found on more expensive electric bicycles.
There are both advantages and disadvantages of each type of motor. This also varies depending on the manufacturer, but generally speaking, there are some known pros and cons when it comes to these motors. Let’s have a look.
Pros and cons of Hub Motor
An E-bike with a hub motor is often more affordable due to its cheap production costs. As mentioned before, there is either a front or a rear hub motor, and this will impact the way the bicycle rides. As the hub engine is positioned on the wheel, spinning the wheel directly, riders tend to feel like they are being pulled (front hub motor) or pushed (rear hub motor) along. This can be great for people with joint or hip problems, as it requires less pedal effort but still generates great power. Perfect for use as a rehabilitation tool.
As the engine is independent of the gears, the rider does not need to change its pedal stroke to reduce chain and cassette wear. Instead, it can pedal through the strokes like on regular push bikes.
In addition, the hub engine and the pedal drive system are completely independent, meaning riders can lose one - say for example the chain - and still be able to ride home on just the electric power. Or if the engine fails, then the chain system will still work. This is great for longer rides, if something happens and the rider is far from home, they can still continue pedalling.
Because the hub is positioned on the bike wheel, it is more exposed to the environment and faced with a higher risk of something loosening in the hub - therefore often needs more maintenance than a mid-drive.
However, hub engines do help minimise other bicycle wear as the hub does not connect to the main pedal drive system. Meaning it does not add any extra stress to the chain or shifters, and therefore does not cause any wear to those parts. If anything, the eBike’s chain will probably last longer than a regular bike because the hub motor is doing most of the work, allowing the chain to rest.
The disadvantage of the motor is that it only allows a single gear ratio. While this is normally not a problem on straight roads and lower speed riding, but having a higher gear option would have been beneficial for uphill climbs.
These bicycles are also often more heavy than a mid-drive bike. Along with the fact that the hub is positioned either at the front or back, it can cause the feeling of weight imbalance. And riders tend to feel like the bicycle is unnatural to handle due to its push and pull feel.
In other cases, the added weight might be positive, as it might be nice to have that extra weight either at the back or front of the wheel. This makes the most sense on electric bicycles with rear positioned batteries, as having the motor in the front would offset the weight imbalance and stabilise the motorized vehicle. In addition, hub bikes are considerably quieter when operating than mid-drive bicycles.
Pros and cons of Mid-drive Motor
The mid-drive motor was created to improve some of the shortcomings identified in a hub engine.
In general, mid-drive engines are considered more of an efficient, comfortable and balanced ride than a hub drive. Riders tend to feel more natural maneuvering this type of vehicle.
The mid-drive is located in the centre of the bike, right underneath the rider, meaning riders tend to feel more balanced and allows for more of a natural feel when maneuvering the motorized bike than with a hub-motor. A great example of this is the SmartMotion Mid City e-Bike which provides smooth power output without jerking the vehicle.
The biggest advantage of a mid-drive motor is that they require little to no maintenance, as the engine’s components are enclosed in the motor casing. This element also provides more protection against the environment than a hub motor.
Another benefit that mid-drive engines have over hub engines is their gear ratio. The gear ratio enables the rider to spin the back wheel through the same gear and chain set as the pedals. This means that a low gear is available for quick accelerating at a stand-still position or steep uphill climbs with massive torque. It makes it possible for mid-drive bicycles to easily power through uphills in low gear than a hub motor.
Additionally, mid-drive motors are known to be lighter and smaller than a hub motor of the same class of motor power. Specialized recently introduced the Specialized Turbo Levo SL a series of Specialized SL 1.1 mid-drive electric mountain bikes weighing down to only 17.5kg. The harder you pedal with these bikes the faster and further you go.
The disadvantage of a mid-drive engine is that it can be harsh on your drive system. Snapped chains are probably the most frequent maintenance issue when it comes to mid-drive e-bikes. Riders also need to pedal harder in order to generate power, which might not be ideal for someone with ligament problems looking for a rehabilitation tool. But great for someone looking for a workout while earning the benefits of considerably more power, distance range and speed.
Even though the bicycle’s motor is an important component of the bike, there are other features you need to consider when buying an e-bike in order to find one that is perfect for your riding style.
Check out our Electric Bikes Buying Guide for more tips on what to look for when purchasing your ideal ride.