Belt Groan Sound

The belt in wet conditions will often make a pronounced new noise from when it's in dry conditions.

Variations

This thread describing a loud buzzing sound on acceleration has audio samples and discussion about how it occurs.

Description

This groaning noise has been called many things from a Tie fighter or a Wookie to a water buffalo.

Effects

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.

References

Groan sound : anybody having specific references for a pure silicone lubricant