Pedal assistance and sensors

An e-bike uses a battery and motor to provide assistance while cycling. When you get assistance, and how much, is determined by sensors. All e-bikes are equipped with a speed sensor. This sensor measures how fast you are travelling and ensures that assistance cuts out as soon as you reach a speed of 25 kilometres per hour. The way in which assistance is provided while cycling is determined by the type of sensor. You have a choice of two types of sensor.

Rotation sensor (or motion sensor)

The rotation sensor senses whether the pedals are rotating. Assistance will kick in with a small delay as soon as you start pedalling. This means that an e-bike does not provide assistance immediately when you set off. The assistance will not be perceptible until after around one revolution of the wheels. If you stop pedalling or apply the brakes, then the assistance will cut out after a small delay. It makes no difference to the rotation sensor how much force you apply to the pedals, you will always get maximum assistance. The degree of assistance is determined on the basis of the speed in the selected setting.

Advantages

  • This simple system means that the rotation sensor is highly reliable 
  • The system is cost-effective 
  • You get assistance all the time, regardless of how much force you apply to the pedals

Disadvantages

  • The assistance is not immediately perceptible on setting off 
  • The assistance can feel unnatural because it is based on rotation rather than pedal force 
  • The rotation sensor draws more power from the battery

Pedal force sensor

The pedal force sensor senses not only whether the pedals are rotating, but also how much force you are applying to them. The motor is controlled on the basis of this information and provides more or less assistance directly. You don't notice any delay with it. It means you get exactly the right assistance while cycling. The force sensor ensures that the assistance cuts out immediately you stop pedalling or when you apply the brakes.

Advantages

  • The harder you pedal, the more assistance you get 
  • The assistance feels natural 
  • You get assistance as soon as you set off

Disadvantage

Your assistance is only delivered when you apply effort yourself

Difference between sensors

Would you like to know how the various sensors work and what the difference is between the 2 types of sensor? See the explanation in a video.