M620 new quieter gear comparison

[TDA78]

I attached audio of the old and new, quieter M620 rotor and third gear from Green Bike Kit. The first 3 seconds are the old gears, the last 3 seconds are the new gears. My old gears look practically new, so you're not hearing worn out gears.

Recording conditions were carefully controlled. Automatic Gain Control (AGC) was turned off. I climbed the same hill, in the same gear, at the same speed, with the same assist level. 20 MPH, drawing 1250 Watts at a cadence of 110 RPM up a 10% grade. The microphone was in the bottle holder on a Dengfu E22 frame, so you can hear wind noise from my leg going by.

Applying A-weighting, I measure a 3 dB decrease in sound level, which is 50% quieter. A-weighting is used to measure perceived sound levels, which happens to also greatly reduce the wind noise.

Not only are the new gears quieter, but I think the tone is more pleasant as well.

Edit: Installation of a new rotor requires calibration of the controller.

 

[Gionnirocket]

...

I have a 2023 bike and just reached 1k mi this week... but haven't cracked the motor open to inspect or grease it yet.
I'm assuming I don't have the new gears as to me it's loud, especially when compared to a BBS02B. It sounds like a super charged electric can opener.
That said it's not annoying most of the time so I'll probably hang with it as is for the time being.

 

[Tom@WashDC]

I attached audio of the old and new, quieter M620 rotor and third gear from Green Bike Kit. The first 3 seconds are the old gears, the last 3 seconds are the new gears. My old gears look

Thankyou for taking the time to do the recording and posting the results.
~Tom

 

[JRA]

After applying John Deere Cornhead grease to my stock M620 it is virtually silent and see no need for it to be quieter. But glad you have gotten to where you want to be also.

 

[Tom@WashDC]

After applying John Deere Cornhead grease to my stock M620 it is virtually silent and see no need for it to be quieter. But glad you have gotten to where you want to be also.

Same results here

 

[Rome]

My m620 is not quite compared to Brose motor on my other bike. The sound it makes is satisfying to the ear though just a low buzzing sound that's all. What annoyed me before was the gentle sound of tapping riding on rough terrain when no load on the motor I could hear the gears bouncing or rattling more like it.

 

[George of the jungle]

I attached audio of the old and new, quieter M620 rotor and third gear from Green Bike Kit. The first 3 seconds are the old gears, the last 3 seconds are the new gears. My old gears look practically new, so you're not hearing worn out gears.

Recording conditions were carefully controlled. Automatic Gain Control (AGC) was turned off. I climbed the same hill, in the same gear, at the same speed, with the same assist level. 20 MPH, drawing 1250 Watts at a cadence of 110 RPM up a 10% grade. The microphone was in the bottle holder on a Dengfu E22 frame, so you can hear wind noise from my leg going by.

Applying A-weighting, I measure a 3 dB decrease in sound level, which is 50% quieter. A-weighting is used to measure perceived sound levels, which happens to also greatly reduce the wind noise.

Not only are the new gears quieter, but I think the tone is more pleasant as well.

Edit: Installation of a new rotor requires calibration of the controller.

I bought a newer M-620 motor with the newer grars and I took the case off to check the grease they put in (been a problem with little grease), anyway I was going to put more grease in if needed.. To my surprise it had lots of grease in it but it is a dark grease and feeles like Never seez. I left it alone and installed the moter... The Motor is complwtely quite.. All I hear now is tire noise. I would like to find out what kind of grease it is.