Symptoms
Engine suddenly makes a lot of noise and vibrates while driving at low speed. The symptoms are permanent when the engine is shifting. When the engine is off, the Stromer runs silently.
Possible causes
Motor cable plug connection(s) & water
When riding in the rain, water can enter the motor cable connector(s) and cause problems. It often helps to unscrew the connector(s), clean them with compressed air and then allow them to dry. [More...]
Motor cable
The motor cables on the motor side can also be affected, as they run very close to the brake disc. It is important to ensure that the cable ties are present and that the cable(s) are resting on the chainstay. See pictures below.
Engine mounts, Bearing play or wear
Play in the bearings or defective bearings can lead to vibrations and thus to a humming noise. Defective engine bearings are often caused by water ingress. With increasing mileage, normal wear and tear also comes into play. [More...]
Loose stator magnets
It is very rare for stator magnets to come loose. The motor must be opened for repair.
[More...]
Hall sensor(s) defective
If a Hall sensor is defective, the electronics can no longer determine the position of the motor. This results in irregular running, noise and problems with the support. [More...]
Possible solution
Before replacing or repairing the entire motor, the following points should be checked for correct connection:
- motor cable to the controller. Older models have three of them.
- HIGO screw connection(s) on the left-hand chain stay
- Engine cable on the engine side. On the ST2 (2016) / ST2S, there were occasional failures because one of the three motor phase cables was broken.
See also PROBLEMS - MOTOR - 'Repairs'