Rubbing noise from my motor

[Mussels]

When I'm moving fairly quickly and power is applied to the motor then I get a cyclic rubbing noise as if the windings or the gears are rubbing once every rotation, I'm not sure how it compares to wheel rotation as I don't know how fast they are spinning. It doesn't happen at low speeds or if there is no power to the motor so I'm assuming the problem has to be between the controller and the motor freewheel, does it sound familiar to anyone?

Edit: it's a SB geared rear hub motor on a Wisper 905.

 

[flecc]

The internal freewheel can make a noise at the point where the road speed is just going beyond the assist limit since it's then in limbo, somewhere between engaging and not engaging. I can't say that's definitely it, but a noise at that point is quite common. If it disappears just below and a little above that assist cut-off speed, it's probably the answer.
.

 

[Sir_Bob]

oudie mussles

Sound like you need a new motor , try contact Gorman.

thx

bob

 

[Mussels]

The internal freewheel can make a noise at the point where the road speed is just going beyond the assist limit since it's then in limbo, somewhere between engaging and not engaging. I can't say that's definitely it, but a noise at that point is quite common. If it disappears just below and a little above that assist cut-off speed, it's probably the answer.
.

It could be that as the noise is there most of the time, unfortunately wind noise is too high above the cut off speed to hear it. I've never heard it before though.
Alternatively I'm hoping it's something like the side of an orbital gear brushing the side of the casing, somewhere it doesn't really matter. I'd expect the orbital gears to still go round when I shut off the power so it's not going to be them.

 

[Mussels]

oudie mussles

Sound like you need a new motor , try contact Gorman.

thx

bob

Would that be Dave Gorman? He gets around a bit that lad.

 

[dicklaiwisper]

Gears

Hi Andrew it sounds to me that the nylon gear wheels may be worn.

If it gets worse please contact Norman, (or Gorman ), he will send you a new set, they are easy to change and will take about 20 minutes after you have taken the back wheel off, so about 14 hours 20 minutes!

All the best David (on Dick's compter)

 

[Mussels]

Hi Andrew it sounds to me that the nylon gear wheels may be worn.

If it gets worse please contact Norman, (or Gorman ), he will send you a new set, they are easy to change and will take about 20 minutes after you have taken the back wheel off, so about 14 hours 20 minutes!

All the best David (on Dick's compter)

Thanks David, to change them do I need to remove the freewheel gears when the wheel is off?
A rather stupid idea of mine was to get a Sun Tour freewheel for which I have no removal tool, I was happy to remove it destructively when worn out but didn't think about taking it off for any maintenance.
Shimano next time.
And is this likely to be a sudden catastrophic failure or will it just slowly get worse until it irritates me into fixing it?

 

[flecc]

Thanks David, to change them do I need to remove the freewheel gears when the wheel is off?

Pending David coming in, if you can get to the side cover screws while the freewheel is in place, you can do the job without removing the freewheel since the gears are on the left hand side within. After removing those side cover screws, take off the left hand nut that keeps the entire inner assembly in the hub, give a sharp tap to the end of the spindle using a mallet or similar to release the cover from the hub shell and the entire inner with side cover and freewheel etc can be withdrawn. You'll then see the gear assembly and the replaceable rack inside the hubshell. These gears can fail suddenly:

N.B. Watch out for any shims on the end of the spindle that might fall off inside the hubshell and make sure you put them back when reassembling. Reverse the procedure when reassembling and tighten that external nut fully to get the internal positioning correct.
.

 

[Mussels]

Thanks, I'll have a look in a bit to see if I can get to the screws. The largest cog is 28 teeth so I'm hoping I can do that.

These gears can fail suddenly:

Oh dear, the noise has been getting louder so I think I'd better get onto Norman.

 

[Bigbee]

Piggy back with Norm may not give the same speed or distance,just a thought.

 

[Mussels]

Piggy back with Norm may not give the same speed or distance,just a thought.

1234567890

 

[Wisper Bikes]

Replacement cogs

Hi Mussels

Flecc is absolutly on the ball as usual, you certainly don't need to destroy anything as this is a perfectly normal maintenance procedure for radial gear hub motors, it really does only take about 20 minutes.

It would be worth changing them sooner rather than waiting for more teeth to go.

All the best David

 

[Mussels]

Hi Mussels

Flecc is absolutly on the ball as usual, you certainly don't need to destroy anything as this is a perfectly normal maintenance procedure for radial gear hub motors, it really does only take about 20 minutes.

It would be worth changing them sooner rather than waiting for more teeth to go.

All the best David

The destroying part was refering to the freewheel that I fitted but don't have a removal tool for, fortunately there is enough room to get to the motor screws so all is good.
I don't fancy being without power to get to work so I'll do it soon after I get the parts.

 

[Wisper Bikes]

Good news!

Have you spoken to Norman about the parts?



Wow image is huge, does anyone know how did I do that?

All the best David

 

[Mussels]

Have you spoken to Norman about the parts?

I have, he suggested some other bits to check first and he's shipping the gears out to me today so I'll know later this week what condition the old gears are in.

 

[flecc]

Wow image is huge, does anyone know how did I do that?

It needed resizing in an image editor David, that's the pixel dimensions, not the file size. Here I've copied your
photo and halved it's size from the 1210 x 985 pixels that you posted to this 605 x 493 pixels, then jpg
compressed it's file size to 70% of maximum to meet the forum requirements:

 

[Mussels]

Well I finally got round to it, the job wasn't too hard and I didn't have to disconnect the electrics. Getting the cogs off was a bit of a pain as I don't have a tiny hub puller, it took about an hour in all.
David was spot on, one cog was complete, one had a tooth missing and the last had over half the teeth missing. I wouldn't have associated the rubbing noise with missing gear teeth but that's exactly what happened, maybe it was the broken off teeth getting caught that caused the noise.
It all runs well upside down, now to finish putting it all back together.