this post was submitted on 30 Mar 2025
11 points (100.0% liked)

bike wrench

1004 readers
1 users here now

A place to ask bicycle repair questions, and for bike shop monkeys to share advanced non commercial wrenching resources (no YouTube self promotion). This is only for repair related topics.

!bicycles@lemmy.ca

!micromobility@lemmy.world

founded 2 years ago
MODERATORS
j4k3@lemmy.world
11
Trying to locate a "creak" sound coming somewhere around the motor of my mid-drive e-bike (feddit.uk)
submitted 3 months ago* (last edited 3 months ago) by Opinionhaver@feddit.uk to c/bikewrench@lemmy.world
3 comments fedilink hide all child comments
 

I serviced the motor about a year ago and didn’t notice anything alarming inside. One of the bearings was a bit dirty and rusty, but I managed to clean and lubricate it, and the noise doesn’t quite sound like a bad bearing.

I can only hear it on alternating pedal pushes. If I just jump on one pedal, there's no sound, but if I shift my weight from one side to the other, it appears. I'm starting to suspect it might be coming from the motor mounts - maybe there's some flex and it's rubbing against the frame - but I'm not sure, and I don’t really know what to do about it either. Sometimes the noise disappears entirely, while other times it gets exceptionally loud.

All I know for certain is that it's not the pedals or the cranks. I cleaned the mounting surfaces and bolts with acetone, but that didn’t help. Then I tried the opposite and greased them, but that didn’t make a difference either. At this point, I really don’t know what to try next. I’d rather fix it myself than take it to a bike shop.

The bike is GZR Black Raw and the motor is Bafang M400

you are viewing a single comment's thread
view the rest of the comments
[–] ALiteralCabbage@feddit.uk 7 points 3 months ago* (last edited 3 months ago)

Creaks can be tricky on any bike but I'd work my way from cheap to expensive which it sounds like you're already doing.

  1. Pedal bearings (sounds dumb but there's nothing worse than spending hours on stripping a bike and finding that it's just a bum pedal!).
  2. Crank arms - check the torque and, for peace of mind remove, grease, and refit (ensuring correct torque).

Since you've done these then it's tike for a bit more in depth work. The next two I usually do simultaneously:

  1. Motor housing - see above, grit and grime can get in and cause noise. Remove, clean, refit, and potentially a touch of grease on contact points.
  2. Motor mounts - this is 99% of the time the culprit of the creaking occurs on both sides of the bike and can be replicated with the bike static. As with everything else: remove, clean, grease and and all contact points and replace, with correct torque. I've done lots of Bosch equipped bikes with similar symptoms as yours which this resolves.

If this doesn't sort it then it's likely internal: bearings, etc. some of these are sometimes user serviceable and they're the typical culrprits, but worst case it's bike shop time...

Edit! Just a quick post-script to this now I've had a few coffees - often I've had experiences where motor bolts are just a little under torque, so it's always worth a quick nip up to spec before you start taking stuff out!