Bearings gone I think in wheel.

Michael Love

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Aug 26, 2018
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I think the bearings have gone in my rear wheel that has the motor on it I do not know how to extract the bearings because the axle would stop any bearing puller.
Sometimes with the wheel on the bike and me riding the bike, the motor sounds like it is locked up but the wheel keeps turning freely because I can pedal, sometimes the wheel sounds awful like it is scraping against something(not the brakes) just at part of a revolution when the motor is driving the wheel, and sometimes the motor drives the wheel like nothing was ever wrong with it.
I have had the motor out and can see nothing wrong. There are no teeth missing and there is no feeling of roughness when I turn the planetary gears manually.
With the wheel off the bike and the motor in the wheel as normal, if I spin the wheel the way to make the planetary gears work, the wheel sometimes just locks up. Spin the wheel the other way and it freewheels just fine but I do hear bearing rattles spinning it either way


Any ideas?
Thanks
 
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Andy-Mat

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Oct 26, 2018
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I think the bearings have gone in my rear wheel that has the motor on it I do not know how to extract the bearings because the axle would stop any bearing puller.
Sometimes with the wheel on the bike and me riding the bike, the motor sounds like it is locked up but the wheel keeps turning freely because I can pedal, sometimes the wheel sounds awful like it is scraping against something(not the brakes), and sometimes it drives the wheel as normal.
I have had the motor out and can see nothing wrong. There are no teeth missing and there is no feeling of roughness when I turn the planetary gears manually.
With the wheel off the bike and the motor in the wheel as normal, if I spin the wheel the way to make the planetary gears work, the wheel sometimes just locks up. Spin the wheel the other way and it freewheels just fine but I do hear bearing rattles spinning it either way


Any ideas?

Any ideas?
Great, but very worrying, description.
I can almost "feel" what you are experiencing, just from your words!
If it was my bike, I would remove the wheel (rear I would guess) with the motor, look at the internet for my motor, similar/same problems, and how to take it apart.
You will probably need some good quality (last a life time!) extra tools. Buy them as you need them I feel, rather than "shotgunning" the problems.
I hasten to add that I have absolutely no experience with the sort of problem you have.....though if you are lucky, it will only be a ball/roller bearing, and they are usually easy to find and buy!
The secret with bearings is top quality replacements!
I hope that some other members here can give you some REAL help.
Best of luck and keep us informed.
Andy
PS. If you still have a guarantee, let the supplier do the work!!
 
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Woosh

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May 19, 2012
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check the motor connections first. If one of the 3 phase wires is disconnected, the motor may exhibit those symptoms. Where about do you live?
 

vfr400

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Jun 12, 2011
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No need to take the wheel off. The cause is not in the motor. It's an electrical problem caused when the timing of the pulses from the controller don't match the motor, which gives the effect like it's being repeatedly hit with a hammer.

Check that the motor connector is pushed in all the way to the marked line, not just in tight. After that, you have to see what connectors there are at the controller end and make sure that they're all tight. It can also happen when the motor wire is damaged, especially where it comes out of the axle. If it is damaged there, you'll probably need a new motor.
 

Andy-Mat

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Oct 26, 2018
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check the motor connections first. If one of the 3 phase wires is disconnected, the motor may exhibit those symptoms. Where about do you live?
If motor connections get shorted, even partially shorted they might, but simply open circuit not.
Its easy for anyone to test, simply pop the three power wires going to the motor and spin the wheel/motor, then short them together and try spinning it again.
Huge difference!
This is used as a braking/stopping system on many products from quality power drills, Locos with electric drive and dock cranes, to name a few, justto slow them down and or stop them safely.
If anyone has further interest, try looking here:-
Regards
Andy
 

Michael Love

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Aug 26, 2018
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Hi Guys,

Thanks for your replies, but I did say I had the wheel off and was spinning it, what I didn't say was that I was spinning it manually so no electirical input at all, that's why I think it is the bearings.

Thank you.
 

Woosh

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May 19, 2012
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take the wheel off the bike, use a 10mm spanner to turn the axle clockwise and anticlockwise.
Post a 20 second video, we can probably tell you what's wrong with it.
 

Nealh

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Aug 7, 2014
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If you can feel roughness of bearing when manually rotating the axle them often it is the end plate bearing that is worn. Once the end plate /cover plate has been removed you can drive the bearing out with a rubber mallet and a socket of the correct size. The bearing number will be on the bearing seal on both sides, to replace a bearing place the end plate on a an even surface or across some timber support, place the bearing by hand in place and simply drive it home with a blow from a rubber mallet and a drive tool (correct size socket will work fine). When refitting the drive tool needs to sit on the circumference of the bearing casing and not directly on the seal.

On the Bafang CST and some axles there is a larger central bearing of about 40mm or so this one if bad can be simply lifted off with out a bearing puller, a couple of wide blade screw drivers can be inserted under the bearing (opposite each other ) and both used as a lever to lift the bearing off as you go around the bearing.
 

vfr400

Esteemed Pedelecer
Jun 12, 2011
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If motor connections get shorted, even partially shorted they might, but simply open circuit not.
Its easy for anyone to test, simply pop the three power wires going to the motor and spin the wheel/motor, then short them together and try spinning it again.
Huge difference!
This is used as a braking/stopping system on many products from quality power drills, Locos with electric drive and dock cranes, to name a few, justto slow them down and or stop them safely.
If anyone has further interest, try looking here:-
Regards
Andy
That doesn't hold for a geared motor when you rotate it forward because there's a one way clutch, but can explain why the motor locks when turned backwards.
 
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vfr400

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Jun 12, 2011
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When you have the wheel off the bike, you turn the wheel backwards and it intermittently locks, in most cases it's because you didn't insulate the bullets on the end of the cable. Try it again, but making sure that they can't touch each other or anything else before judging what's wrong.

If the motor has the short cable with the moulded 9-pin connector and it's disconnected, shorting is less likely but can still happen when you damage the cable where it comes out of the axle.

The bearings may or may not be worn. All the worn ones I've seen were rusty as well. I've never heard of or seen worn bearings lock the motor. Locking happens when you have a cable fault, connection fault or controller fault. The only other cause is rust, but that's really obvious.
 
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Andy-Mat

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Oct 26, 2018
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That doesn't hold for a geared motor when you rotate it forward because there's a one way clutch, but can explain why the motor locks when turned backwards.
It actually is true for almost any motor, AC or DC.
I was talking about the motor only, and it does "brake" the motor only when 2 or more connections are in some way shorted together.
It is very easy to test out, one of the easiest tests one can make. When I do it, I keep the connections apart, spin up the wheel, and note how long it takes to stop, then spin it up again, and short the connections.
For good intact motor field windings, it is usually stopped within 1-3 revolutions! Very easy to see.
If a field or connection is open circuit, then when say only using two connections instead of the three, when the damaged winding is in circuit/test, the wheel will simply continue spinning.
Or if a higher resistance damage is apparent, it will slow down "slower", if that makes sense.
What gearing does is a separate matter, but possibly difficult to separate from a motor problem, without taking things apart!
But of course defective bearings in the gearbox may of course further complicate the diagnosis a lot!
We will all have to wait and see what the final result is....:):).
Andy
 

Michael Love

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Aug 26, 2018
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take the wheel off the bike, use a 10mm spanner to turn the axle clockwise and anticlockwise.
Post a 20 second video, we can probably tell you what's wrong with it.
Hi,
I really thank you all.
I have posted pics and videos here.

I will short a winding when doing a spin test.
Meter tells me 140ohms between any of the three phases. I have not tried any phase to ground test yet.

I am wary about trying to take the cap of the axle as I do not want to break it.

How do I take the large bearing/ flywheel off that holds the planetary gears?



Thank you.
 
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Nealh

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You are better to post pics on here then for us to go to a third party site.
 

Nealh

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I couldn't here anything on the video's and the hub rotated quite well.
The end plate bearing if rough you will be able to feel it and here it as you rotate the axle slowly, other wise the planet gearing is lacking grease. Clean it up and regrease with a non petroleum grease and don't spare the grease.
 
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Nealh

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Double check the bullets connections at the motor end, as they may cause an issue.
Think about soldering direct or solder in a julet 9 pin connector.
When testing phase expect to see about 9 ohm to 15 ohm or so, all three should be the same, do the same for phase to V+. You may see the same or possibly the three readings will all read one which is good and zero reading is bad.
 
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Michael Love

Pedelecer
Aug 26, 2018
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Double check the bullets connections at the motor end, as they may cause an issue.
Think about soldering direct or solder in a julet 9 pin connector.
When testing phase expect to see about 9 ohm to 15 ohm or so, all three should be the same, do the same for phase to V+. You may see the same or possibly the three readings will all read one which is good and zero reading is bad.
Lol, it was probably 15ohms, my eyescare getting worse.
Thank you.
I think I wii post pics here so they are avail for others to see in the long term.
 

Michael Love

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Aug 26, 2018
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Videos too large to upload.
 

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Nealh

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Aug 7, 2014
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I can faintly hear a noise but it doesn't impede the motor turning by the looks of it.
If a bearing is at faulty you should be able to feel it if you have your hand on the axle and rotate the wheel by hand.
Show us a pic of the inside of the removed cover plate .
Also check the freewheel gear cluster, manually rotate them does it feel rough.
 
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Michael Love

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Aug 26, 2018
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Just pulled the motor out again with the view to replacing the hub bearings.
Is this clip meant to be loose? Anyway, O have replaced it with a new one the same size and the new on is tighter and is located in its slot and doesn't move.


Here's the bearings, I am going to go by the numbering, if that is wrong, please let me know.
They are a little rough when trying to spin them, but I might as well replace them now that they are out.

Thanks.
 
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