Strange slipping sensation after complete new drivetrain. Could it be the motor?

[jonathanbaird]

Hi,

I have a weird issue which I'm hoping somebody could point me in the right direction on... Recently I have noticed a strange slipping/skipping sensation when pedaling my bike, usually when under load but not always. I took this to the LBS and they installed a completely new drivetrain (derailleur, chain, chainring and cassette) but I still have the same problem. I took this back to them at weekend and it seemed like one of the teeth on the freehub was sticking slightly but other than that there was no wear to the freehub. This was cleaned out and put back together for me to try again but it seems the issue is still there.

Other than the freehub, is there anything else this can be? It's worth mentioning I needed a new rim a couple of months ago and the issue 'seems' to have been since then but it's possible I've only just picked up on it since then. Is there anything in the hub itself or even in the motor that could be causing this slipping? Could it be an issue with the wheel rebuild following the rim replacement? I need to contact the LBS again for them to investigate further but having spent £300+ on a whole new drivetrain already I'm somewhat reluctant to just keep throwing money at it. In all fairness since the drivetrain has been replaced the bike shifts like new but I'm just left with this niggling issue!

The problem I have is it's a really intermittent issue and doesn't really cause me any issues, it's just niggling more than anything else but difficult to replicate for them to see it. Has anybody had anything similar or does anybody have any suggestions as to what this could be? I have the Bosch CX Gen 4 Motor if that's relevant but it seems the LBS is at a loss as to what it is at the minute. Any pointers would be much appreciated!

Thanks.

 

[silles]

Hi,

I have a weird issue which I'm hoping somebody could point me in the right direction on... Recently I have noticed a strange slipping/skipping sensation when pedaling my bike, usually when under load but not always. I took this to the LBS and they installed a completely new drivetrain (derailleur, chain, chainring and cassette) but I still have the same problem. I took this back to them at weekend and it seemed like one of the teeth on the freehub was sticking slightly but other than that there was no wear to the freehub. This was cleaned out and put back together for me to try again but it seems the issue is still there.

Other than the freehub, is there anything else this can be? It's worth mentioning I needed a new rim a couple of months ago and the issue 'seems' to have been since then but it's possible I've only just picked up on it since then. Is there anything in the hub itself or even in the motor that could be causing this slipping? Could it be an issue with the wheel rebuild following the rim replacement? I need to contact the LBS again for them to investigate further but having spent £300+ on a whole new drivetrain already I'm somewhat reluctant to just keep throwing money at it. In all fairness since the drivetrain has been replaced the bike shifts like new but I'm just left with this niggling issue!

The problem I have is it's a really intermittent issue and doesn't really cause me any issues, it's just niggling more than anything else but difficult to replicate for them to see it. Has anybody had anything similar or does anybody have any suggestions as to what this could be? I have the Bosch CX Gen 4 Motor if that's relevant but it seems the LBS is at a loss as to what it is at the minute. Any pointers would be much appreciated!

Thanks.

my gf had a gazelle cityzen with a bosh motor which was doing something similar.
it was the motor, think there is a cluch in it which after a while it start slipping. it feels like when u have a worn chain/cassette but in this case the slipping come from the motor. so the chain wont move. just the crank spins


[that bike has done more than 16000 miles. ]

 

[jonathanbaird]

my gf had a gazelle cityzen with a bosh motor which was doing something similar.
it was the motor, think there is a cluch in it which after a while it start slipping. it feels like when u have a worn chain/cassette but in this case the slipping come from the motor. so the chain wont move. just the crank spins


[that bike has done more than 16000 miles. ]

I've just come across this thread Impossible Bosch Ebike Issue which seems to sound like a similar issue... It does feel though like it could be the motor. I've done something like 2700 miles on mine so nothing like 16000! I wonder if such an issue is covered by warranty with Bosch...

 

[silles]

I've just come across this thread Impossible Bosch Ebike Issue which seems to sound like a similar issue... It does feel though like it could be the motor. I've done something like 2700 miles on mine so nothing like 16000! I wonder if such an issue is covered by warranty with Bosch...

it should be. ours was way out of warranty and not worth the repair.

 

[Stihldog]

The first thing that came to mind was a faulty hub. Worn pawls, missing springs too much grease etc. Since you’ve upgraded the drivetrain and the LBS replaced the rim…maybe? Hopefully it’s only a hub issue and not the motor .