Electric bikes are now one of the most popular ways to ride in the UK, whether for commuting, leisure cycling or longer touring routes. But with so many different motor systems, battery sizes and brands available, understanding how electric bikes actually work can feel overwhelming.
This guide explains electric bike motors, the difference between hub drive and mid-drive e-bikes, how they’re powered, and what separates the major motor brands — so you can make sense of the technology without the jargon.
How Do Electric Bikes Work?
At their core, electric bikes (also known as e-bikes) are standard bicycles with an integrated motor that provides assistance when you pedal. TMany people think e-bikes are like mopeds with a throttle, but that isn’t the case. An e-bike only helps when you pedal. Sensors detect your movement and activate the motor, and you can adjust the level of assistance depending on how much support you want.
A typical e-bike includes:
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an electric motor
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a rechargeable battery
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sensors that detect pedalling effort or movement
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a controller that manages how power is delivered
In the UK, road-legal electric bikes (EAPCs) must:
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have a motor rated at 250 watts
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provide assistance only up to 15.5mph
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require pedalling for the motor to work. Bikes can however have a ‘walk start’ function which is a button or throttle that kicks the motor in up to 4mph.
Understanding these basics helps avoid confusion — and accidental purchase of an illegal e-bike.
Hub Drive vs Mid-Drive E-Bikes: What’s the Difference?
One of the most searched questions around e-bikes is the difference between hub motors and mid-drive motors. The distinction matters more than many people realise.
Hub Drive Electric Bikes
A hub motor is built into the centre of the front or rear wheel. The motor works inside the hub so directly moves the wheel directly.
How hub motors feel
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steady, consistent assistance
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more noticeable “push” from the motor
Advantages
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simpler design
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often cheaper
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reduced wear on chains and gears
Disadvantages
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less efficient on hills
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heavier wheels
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less responsive to rider effort
- Strain on the spokes can often lead to snapped spokes and cracked eyelets.
Hub drive electric bikes are common for:
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commuting
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leisure riding
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flat or gently rolling terrain
Mid-Drive Electric Bikes
A mid-drive motor sits at the crank, powering the bike through the drivetrain. The motor directly puts power through your pedals giving a more progressive feeling and reacts to the pressure you put through the pedals.
How mid-drives feel
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very natural assistance
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power increases as you pedal harder
Advantages
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excellent hill climbing
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better balance and weight distribution
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improved efficiency
Disadvantages
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higher cost
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increased drivetrain wear
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more complex servicing
Mid-drive systems are popular on:
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touring e-bikes
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electric mountain bikes
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long-distance leisure bikes
E-Bike Sensors Explained: Torque vs Cadence
The way an electric bike responds depends heavily on its sensors.
Cadence Sensors
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detect whether pedals are turning
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provide fixed levels of assistance
These are simpler and often found on hub motor e-bikes.
Torque Sensors
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measure how hard you pedal
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adjust assistance dynamically
Torque sensors create a more natural ride feel and are common on mid-drive systems.
Popular Electric Bike Motor Brands Compared
Many riders search for electric bike motor comparisons, especially when choosing between well-known systems.
Bosch Electric Bike Motors
Best known for: reliability and smooth power delivery
Bosch systems use advanced torque sensing and are widely supported in the UK. They’re often chosen for touring and everyday reliability. Starting from the active line motor up to the performance range they offer a wide range of options. We find Bosch to be the most reliable of the brands and are used on our hire fleet. We haven’t had to use them much but the warranty support on the Bosch motors is top notch.
Shimano STEPS Motors
Best known for: lightweight design and efficiency
Shimano motors integrate closely with their drivetrains, offering a responsive, sporty ride feel that appeals to experienced cyclists. In terms of weight, Shimano comes up trumps in terms of lightweight and efficiency of their motors. They can be sensitive to pressure on the pedals when you start off which causes the W011 error code but once you know its easy to solve.
Yamaha Electric Bike Motors
Best known for: strong torque and durability
Yamaha motors deliver powerful assistance, particularly noticeable on steep climbs or loaded bikes.
Brose Motors
Best known for: quiet operation
Using internal belt drives, Brose motors are among the quietest available and are often found on premium electric bikes.
Bafang Motors
Best known for: affordability and flexibility
Bafang systems vary widely in performance and are commonly used on entry-level e-bikes and conversions. Popular with people wanting to create their own bikes with the Bafang kits. If your looking into e-bike kits we also highly recommend Boost Conversion kits
Electric Bike Batteries: Capacity, Power and Real-World Range
Battery size is measured in watt-hours (Wh), not miles. 400wh is more than enough for most commuters even in hilly cities but we would recommend 625 plus if your looking for a bike for touring.
Typical e-bike battery capacities:
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400Wh – short rides, flatter terrain
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500–625Wh – mixed riding and touring
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700Wh+ – long distances or hilly routes
Actual range depends on:
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rider weight
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terrain
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assistance level
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wind conditions
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tyre choice
Two identical electric bikes can achieve very different ranges depending on how they’re used.
Common Mistakes When Choosing an Electric Bike
Many issues people experience with e-bikes come down to choosing the wrong system for their needs.
1. Choosing a Hub Motor for Very Hilly Riding
Hub motors struggle on long or steep climbs, especially when fully loaded.
2. Focusing Only on Battery Size
A large battery doesn’t guarantee long range if the motor system is inefficient or constantly used at high assistance levels. Hub motors take up a lot more power than mid drive.
3. Ignoring Sensor Type
Cadence-only systems can feel jerky or unnatural for some riders, particularly on stop-start routes.
4. Buying Power Over Practicality
High-torque motors aren’t always necessary for leisure riding and can increase wear and maintenance costs.
5. Overlooking Servicing and Support
More complex systems require proper servicing. Availability of support matters just as much as motor performance. Stick to the big brands!
Which Electric Bike System Is Right for You?
There’s no single “best” electric bike motor — only the one that suits how you ride.
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Urban and commuting riders often prioritise simplicity
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Touring riders benefit from efficiency and torque sensing
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Leisure riders may value comfort over power
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Hilly routes favour mid-drive systems
Understanding the differences between electric bike motors, drive systems and batteries allows you to choose confidently — and avoid costly mistakes.
What bikes do we recommend?
We are of course going to be a bit biased on this but after trying many bikes for our e-bike hire fleet we do highly recommend the Raleigh Motus and Centros range for value for money and performance. If you have any questions about bikes to buy we are always happy to help!