bosch gen 4 rattle, reply from bosch

[Vinnykiwi]

I have looked a little more into this and the noise is not coming, as first thought, from the ratchet. I can feel the ratchet engage and then clonk! There is something else but I just don't have time to strip the motor again yet.

I hope you’ll find time soon, you’ll be a millionaire if you are the one that creates a fix for this problem. Take my money

 

[Bearing Man]

I hope you’ll find time soon, you’ll be a millionaire if you are the one that creates a fix for this problem. Take my money

We have tried, but this issue is not currently fixable It's caused by very slight backlash or "play" in the drive train from the electric motor to the crankshaft. There are a set of very small gears, that each have a tiny amount of play (necessary, not poor engineering) and it's these gears you can hear rattling back and forth as the crank moves slightly over rough ground. The Shimano EP8 suffers the same problem. May be time to get the ear buds out if it bothers you too much.

 

[RustyMTB]

The one I can't work out - I'm on my second Bosch gen 4 bike & ths one - Focus Jam2 is distinctly louder than the last one (Decathlon Stilus) The lads I ride with tell me the motor whines more than me but the only difference between the two I can think of is the Decathlon had a steel bashguard & the Focus doesn't.

 

[Jamze]

I've ridden two models of the same bike (Whyte), one rattles, one doesn't

 

[RustyMTB]

Same. My Jam rattles way more than my Stilus. You tune it out I find but still...

 

[Bearing Man]

The one I can't work out - I'm on my second Bosch gen 4 bike & ths one - Focus Jam2 is distinctly louder than the last one (Decathlon Stilus) The lads I ride with tell me the motor whines more than me but the only difference between the two I can think of is the Decathlon had a steel bashguard & the Focus doesn't.

I've ridden two models of the same bike (Whyte), one rattles, one doesn't

Same. My Jam rattles way more than my Stilus. You tune it out I find but still...

Every eBike motor sounds different. For example: Yamaha's have a distinct gear whine, some are whisper quiet and some are horrendously loud. Same with Brose, some you wouldn't know they are switched on, some are quite obtrusive. And it's the same with the Bosch and Shimano, some are quiet, some are not.
It's worth remembering that there is no sound deadening on these motors, and then they're bolted into a big aluminium or carbon megaphone, so very slight differences in sound tend to get amplified.

 

[Mikerb]

I've ridden two models of the same bike (Whyte), one rattles, one doesn't

that could be cable rattle rather than motor. The models that had the battery electrical connector at the bottom have cables loose in the downtube unless you pull them tight through the grommets. The latest models with the rail mounted battery has less cable noise because they are all clipped into holders at 3 points in the downtube. They can still rattle a bit if not taught............I pushed a bit of neoprene between them and the wall of the downtube to stop that.

 

[Jamze]

Definitely motor rattle/knock. I've ridden E150S, E150RS and E160S (my bike). Only the E160 rattles when coasting on rough descents.

 

[Mikerb]

Definitely motor rattle/knock. I've ridden E150S, E150RS and E160S (my bike). Only the E160 rattles when coasting on rough descents.

it rattles because the chain grabs the chainwheel as the rear triangle compresses and releases.........how much it does that depends on how the rear shock is set up plus the kinematics of the rear end. I get very little rattle on E180 RS. There is little or no rattle on my wife's Cube Gen 4 hardtail.

 

[Akiwi]

I have a solution!!
The other I knocked my Derailleur off at the top of a mountain pass. So, I removed it and the chain and put that in a plastic bag in my backpack. I had to continue down trails and roads for another 15 KM and my bike has never been so quiet!