A low "thunk" comes from motor area (Creo) when pedaling - SOMETIMES

[kahn]

I mention SOMETIMES because the sound happens if I coast and then start pedaling again and the sound will continue while pedaling until I coast again and then it might or might not go away. So another coast and it clears the "thunk" sound. I surmise that something down in the crank/motor interface gets out of sync and then the "thunk" happens and continues until I manage to get the sync right again. Otherwise it is hard to describe. I've thought about firing up the recorder on my phone and see if it can pick up the "thunk" sound and then the absence of this "thunk" sound.

Anyone have similar sounds or symptoms?

 

[mschwett]

i have heard the subtle "thunk" when going from pedaling with assist to not pedaling or ghost pedaling, i always assumed it was the clutch mechanism disengaging the motors gears from the crank. i have never heard it continuously or anything that would require to be "cleared" as you say, it's just a single thunk when the assist disengages.

 

[kahn]

i have heard the subtle "thunk" when going from pedaling with assist to not pedaling or ghost pedaling, i always assumed it was the clutch mechanism disengaging the motors gears from the crank. i have never heard it continuously or anything that would require to be "cleared" as you say, it's just a single thunk when the assist disengages.

No, this continues while pedaling once it starts until I stop pedaling and then start up again. But it does not always clear up unless I again pause slightly and resume - like I suggested - getting it back in sync.

 

[GuruUno]

No, this continues while pedaling once it starts until I stop pedaling and then start up again. But it does not always clear up unless I again pause slightly and resume - like I suggested - getting it back in sync.

I've been noticing a similar (?) noise (thunk or faint click) on my Vado SL 5.0 on occasion. I tested it again yesterday on a 30-mile ride with different power levels, speed, and cadence as well as with no power. It's mostly gone when there is no power and when I use ECO peddling hard it's there. It's a difficult one to pinpoint, but it is from the area of the motor and chainring. I'll most likely replace the chain and inspect it this week to see if anything changes. Also, I can mount my Contour Roam camera down low to capture audio and video to see if it can pinpoint it. I used that same system back when my Trek Super Commuter S8 had motor noises, which the captured video ultimately helped in getting. motor replacement. It's a tough one to pin down.

 

[Mike Moore]

I had a similar issue on my Como 3 and it turned out to be loose motor bolts. Once the bolts were tightened the issue disappeared. Local LBS said it is a frequent occurrence.

 

[Stefan Mikes]

I had a similar issue on my Como 3 and it turned out to be loose motor bolts. Once the bolts were tightened the issue disappeared. Local LBS said it is a frequent occurrence.

These are very different motors.
The reason of the noise can be anything. Some user here was reporting the Creo noise as resulting from TCU cables rattling inside the top tube...