Clattering coming from new CX2020 motor

[Mteam]

No doubt frame material and frame design can have an impact on how much the noise is amplified but I wonder if the design of the rear triangle also has an input and is the reason why some bikes are quieter than others. My wife has the 2020 motor in a Cube Access which is a hardtail and it makes not rattling noise at all. For the same reason it could be that a rear shock set differently in terms of compression or progression ( most probably just beyond the sag point or at the midstroke) may also determine whether suspension movement agitates the chainwheel via the chain.

its the chain growth as the suspension compresses and extends that tugs on the chainring and makes the clattering noises inside the motor, a bike with no chain growth (eg a hardtail) will be a lot quieter than a bike with a lot of chaingrowth.

 

[Mteam]

I have a Orbea WILD FS with the clattering problem. I also have a Focus JAM2 which is silent going downhill over any terrain. I have been going thru this thread trying to see if Bosch has taken an official position on this, or if it's even fixable?

I also have a wild fs - and whilst the motor does clunk a bit, the battery cover on these also rattles a little, if you tap the battery cover towards the bottom with your finger you can hear it knocking against the frame, or if you lift the front of the bike up and drop it down you can hear it knocking.

You can fix it by sticking some rubber or felt on the inside of the battery cover between and either side of the two locating tabs at the bottom of the cover.

 

[Mikerb]

its the chain growth as the suspension compresses and extends that tugs on the chainring and makes the clattering noises inside the motor, a bike with no chain growth (eg a hardtail) will be a lot quieter than a bike with a lot of chaingrowth.

yes I agree but I wondering whether different rear triangle designs or even different freehub designs make for more or less chain movement, and therefore explains why some bikes are noisier than others.

 

[GrahamPaul]

yes I agree but I wondering whether different rear triangle designs or even different freehub designs make for more or less chain movement, and therefore explains why some bikes are noisier than others.

The other thing that will do it is to freewheel with cranks vertical rather than horizontal. That really makes the motor chatter. So much so that I seem to remember Bosch commenting the fact.

 

[Mteam]

yes I agree but I wondering whether different rear triangle designs or even different freehub designs make for more or less chain movement, and therefore explains why some bikes are noisier than others.

Yes different rear triangle (aka suspension) designs will have different amount of chain growth hence more or less clatter.

 

[Meave]

Just updating this post to say I have a 2021 Trek PowerFly 4 and I’m getting this noise and it’s driving me crazy. Has there been a fix for it yet?

 

[Bearing Man]

We are pretty sure we have finally isolated this internal motor noise! Will post a video on here soon

 

[Vinnykiwi]

Awesome, looking forward to it