Belt Groan Sound
From Unofficial Zero Manual
The belt in wet conditions will often make a pronounced new noise from when it's in dry conditions.
- This thread describing a loud buzzing sound on acceleration has audio samples and discussion about how it occurs.
- This groaning noise has been called many things from a Tie fighter or a Wookie to a water buffalo.
- It is completely normal and causes no ill effect on the bike, and will go away again when dry.
- Potential Causes
- The belt being dirty while wet may exacerbate this.
- Encoder Accuracy Hypothesis
- There is a strong perception that the sound comes from the belt, but also an impression that the encoder sensors inside the motor lose accuracy in high humidity.
- This would make the controller think the motor is in a slightly different position, then send the wrong/displaced field to the motor, which would result in an oscillation.
- The motor might be driving the belt to resonate in this case.
- Potential Solutions
- Wait for the bike to dry out.
- Silicone Spray
- Light application of a silicone spray to the motor shaft to the front sprocket should make it go away for months.
Warning: Ensure the spray doesn't have any petroleum distillates that will eat the belt materials.
- The Encoder Accuracy Hypothesis above implies that one should apply it near the front sprocket to protect moisture from entering the motor housing.