Which type of electric motor system is best for a utility bike in Sheffield – Hub motor (in one of the wheels) or a Mid-motor (in the frame)?
An e-bike system consists of a bike with a fitted Battery, Controller and electric ‘engine’ – the Motor.
There are 2 main types of these; either small electric motors in the front or rear wheels (Hub drive) and those with the electric motor positioned down in the frame and putting their power through the pedal axle as you pedal (Mid-drive). This type of drive is also called Chain, Centre or Crank drive. Mid-drives models are generally more expensive as the bike is specifically built around the motor.
To help you decide which is best for you, consider what you want the bike for and where you are going to use it.
In our experience, and in the view of testers and users, the Mid-drive type, although heavier and more expensive, is generally more suitable for utility bikes being used in hilly areas. The electric motor drives through the bike’s gears as you pedal. This means that with the right gear selected the motor is kept running at its optimum speed. This uses the power more effectively and efficiently, particularly on steeper hills.
Our current e-bikes are the Mid-drive type, and we use them as everyday transport for short, often well-loaded utility journeys to work, the shops, the allotment and for social visits in hilly Sheffield.
Hub drives broadly fall into two categories: ‘Full time’ where the user may have the assistance switched on for sustained periods of time, more like a mid-motor user would. This type of system will be relatively heavy, including a chunky battery of a similar capacity to a mid-motor system.
The other, found on lighter e-bikes, is a more on demand ‘power-boost’ system brought into use less frequently and for shorter periods of time, as and when conditions dictate, and so will have smaller and lighter system components (Motor and battery). Much of the time on these bikes will be spent with the assistance switched off, as they are easier to ride unassisted.
There are two types of hub motor. Geared and gearless.
The geared hub motor has planetary gears that step down the RPM of the motor to a much slower speed to drive the wheel.
These can be quite powerful, and may be fine for leisure, commute and lighter utility use around Sheffield.
The gearless ‘direct drive’ hub motor is essentially ‘single geared’ and under ideal conditions – flat or undulating areas and routes – can be very efficient and reliable. However, as the speed of the bike and therefore the wheel drops on significant hills (e.g. marked as greater than 10%) so does the motor’s power and efficiency. On significantly long or steep climbs you simply don’t have recourse to the ‘turbo’ setting degree of power that you can call into play on a good mid motor powered model, and a heavier or loaded rider will need to resort to some really low gears to get up the hill with a similar degree of comfort to a powerful mid drive.
In such a scenario you will definitely want the gear system to feature a lower (than the average e-bike) gear range. This could be a proper old school Mountain bike (MTB) triple or wide range MTB double setup, or, at greater cost, a more modern super wide range ‘1x’ system.
Good article on the differences and advantages of Mid-drive and Hub motors here (but ignore the drive chain stuff – it’s not true.)