Strange creaking noise when pedalling Scott/Bosch fs mtb.

[Gubbins]

Over the past month or so I have started hearing an odd creaking sound coming from the motor region. It's hard to be precise because it is only apparent when pedalling hard and the only way to describe it is a creaking noise at the time pressure is applied and a reverse of the creaking noise when pressure is eased off. The noise is only on the first power downstroke and won't be heard again until I ease off.
Chain and sprockets are good, cranks and wheels are tight and there doesn't seem to be any play in the pivot bearings. Only thing not checked are the motor bolts as I don't know how to get at them..
My feelings are the pivot bearings but no sounds when riding over bumps and no obvious sideways play but I don't know how to test them either..
Any ideas?

 

[Fordulike]

Over the past month or so I have started hearing an odd creaking sound coming from the motor region. It's hard to be precise because it is only apparent when pedalling hard and the only way to describe it is a creaking noise at the time pressure is applied and a reverse of the creaking noise when pressure is eased off. The noise is only on the first power downstroke and won't be heard again until I ease off.
Chain and sprockets are good, cranks and wheels are tight and there doesn't seem to be any play in the pivot bearings. Only thing not checked are the motor bolts as I don't know how to get at them..
My feelings are the pivot bearings but no sounds when riding over bumps and no obvious sideways play but I don't know how to test them either..
Any ideas?

Bikes can develop noises in places where you think they are, but in actual fact are coming from elsewhere. For example, I had a creak sound, similar to yours, which I swore was coming from the headset. Turned out to be a loose seat clamp, which was transmitting the sound along the frame, to give a false impression it was at the front end of the bike.

It's worth checking all nuts and bolts for security.

 

[Deleted member 4366]

Motor bolts need tightening?

 

[redalexx]

@Gubbins I have several questions:

- how old is the Scott bike
- what type of Bosch motor is implemented
- what is the current mileage
- when do you use the bike (p.e. always / just sunny days)

 

[Gubbins]

@Gubbins I have several questions:

- how old is the Scott bike
- what type of Bosch motor is implemented
- what is the current mileage
- when do you use the bike (p.e. always / just sunny days)

It's 9 months old
Bosch cx
1000 miles
Fine weather on road/mild off road (tried the wet stuff and didn't like it)

 

[redalexx]

@Gubbins
the bike is really new, so I cannot imagine that there are problems with the bearings, especially because you do not like the wet and dirty rides. I share @d8veh theory
- motor bolts
- also possible pedals tight? crank arms tight? -> oh i read, you checked already

Bikes can develop noises in places where you think they are, but in actual fact are coming from elsewhere.

Correct, I add my strange sound where I thougth the motor was responsible. The freewheel in the rear wheel. It was an aluminium freewheel and due to the high pedalling forces it deformed and grinded after 2.000 miles. Also Bosch CX!

 

[Gubbins]

How dies one access the motor bolts? I have heard phrases like dropping the motor out but I an assuming it's cranks and covers off for access?

 

[soundwave]

take off the crank arms and remove the case there are 3 bolts that hold the motor on

 

[Gubbins]

View attachment 20443
take off the crank arms and remove the case there are 3 bolts that hold the motor on

Left side only or both?

 

[soundwave]

the bolts are locked in place on the other side so just the left side needs to come off to tighten them.

 

[soundwave]

 

[Steve A]

I've posted noise problems in this area as well. It turns out that the Bosch motor along with drive chain need much more maintenance i.e. cleaning, tightening and lube than any other bike I've ever had.

I think you've covered all the areas I would have, but I had another similar problem to you that only happened when initially exerting pressure on crank and it turned out to be body movement and the carbon seat post wasn't tight enough. Also, check suspension pivots.

I've accepted that my bike will never be totally noise free.

 

[Gubbins]

My noise is definately odd! It doesn't do it until I am 4 miles into a ride then it gets progressively louder.

 

[Deleted member 4366]

It's warming up and expanding.

 

[StewC]

I agree with all points previously mentioned. I would also add, seat post creak, does it still creak when standing up? If noise goes it could be the seat post, I use a thin smear of grease around my seat post where it fits into the frame, this seemed to stop the noise I had.
My Trek Powerfly 7 FS with Bosch CX, as had a creak noise, so I also stripped, and cleaned all rear pivot bearings and re-greased them, head set was also cleaned and lubricated, tightened motor mounting bolts, check pedal arm bolts, as the first ones fitted to my bike kept coming loose, after about 4-5 miles, this was resolved by replacing the pedal arms (under warranty). Bike is not silent, but much improved, with the extra power going through the drivechain, and rear suspension there is going to be stresses to all moving parts that will cause noises, and obviously premature wear of parts. All part n parcel of owning and using an eBike.

 

[Gubbins]

I agree with all points previously mentioned. I would also add, seat post creak, does it still creak when standing up? If noise goes it could be the seat post, I use a thin smear of grease around my seat post where it fits into the frame, this seemed to stop the noise I had.
My Trek Powerfly 7 FS with Bosch CX, as had a creak noise, so I also stripped, and cleaned all rear pivot bearings and re-greased them, head set was also cleaned and lubricated, tightened motor mounting bolts, check pedal arm bolts, as the first ones fitted to my bike kept coming loose, after about 4-5 miles, this was resolved by replacing the pedal arms (under warranty). Bike is not silent, but much improved, with the extra power going through the drivechain, and rear suspension there is going to be stresses to all moving parts that will cause noises, and obviously premature wear of parts. All part n parcel of owning and using an eBike.

Def not any of the obvious which are easy to exclude. After a big ride when its really creaky I can wedge the bike up to the garage wall and press hard on either pedal to make the noise. There is no obvious movement or play anywhere.
Bike is under warranty but from an on-line retailer.
Due to personal issues I haven't had time to look at it properly, but hopefully tomorrow..

 

[soundwave]

id not be surprised if it is that right hand side bearing that is exposed causing it if all the motor bolts are ok esp if you say when you push on the pedals it does it as it dont take much dirt to get a bearing to start failing and grind it in to paste.

 

[Gubbins]

Finally managed an hour to myself so delved in..
Left crank wasnt loose, but wasnt over tight either
All engine bolts tight, but I managed to crack one of them just a tad.
Pivot bearing seemed to be only hand tight so gave it a tweak.. 25Nm?? Is that using a bar 25 meters long? I think not, so just gave it a tweak!!
A quick test ride around the block wont work cos it quiet until it gets warm

 

[Deleted member 4366]

I just remembered, those splined cranks can creak something rotten, and tightening them up doesn't help because they're not tapered like a square taper. I had to grease mine to stop it from creaking. the noise was so loud that it was embarrassing.

 

[Gubbins]

if it was that would they be quiet for 4 or 5 miles before becoming noisy?