- by Jan Dudek
There is no point repeating the cliché that the motor is the heart of the e-bike and one of its key components. Sava uses two basic types of motor for its e-bikes, differing in their location.
The middle motor
The mid-motor location is primarily used on Sava mountain and trekking e-bikes. The advantages of this placement are as follows:
- Precise and smooth transmission of motor power depending on the driving process.
- quiet and smooth motor operation
- ideal weight distribution of the bike, the motor is placed in the centre of gravity
- by selecting the right gearing, you can influence the speed of the bike and the motor, thus achieving the optimum ratio of speed when riding
- to achieve a lower consumption of the bike. The ideal consumption naturally affects the maximum range of your e-bike
- easy removal of the front and rear wheels, for example when you need to replace or patch a puncture
On the other hand, the disadvantages of the central motor are:
- higher emphasis on the quality of the shifter and derailleur adjustment
- lower wheel chain life compared to a normal wheel
- low motor resistance when riding unassisted
We use two types of centre motors for our e-bikes. Bafang and ExtraDrive 500, a motor developed for Sava by Shengyi. We offer an extended warranty of 5 years for this ExtraDrive 500 motor.
We choose this location for Sava folding, gravel and mountain bikes electric bikes. The reasons for this are as follows:
- the motor does not put any resistance when switched off. Therefore, it will run without problems even with a smaller battery capacity, which is what you will appreciate with folding and gravel bikes
- instant acceleration of the bike, again suitable for urban traffic
- minimal servicing requirements
Of course, there are two sides to every coin. And where there are advantages there are also disadvantages. In the case of rear motors these are:
- uneven distribution of the bike's overall weight and the resulting poorer handling. Therefore, an integrated battery is better than a battery on the rear rack, which puts even more strain on the rear of the e-bike
- poorer drive sensitivity when riding due to the lack of a pedal pressure (torsional) sensor
- poorer efficiency against centre motors at higher battery loads
- if you need to replace the rear wheel tube you need a special wrench