TSDZ2 motor slipping

paddymacdaddy

100 µW
Joined
Jan 20, 2023
Messages
7
I have a problem with my TSDZ2 motor, it suddenly has very little power when pedalling or when using the throttle. I can pedal or throttle very lightly to build up speed but the moment I put some effort into it there’s a horrendous loud friction whine that comes from the motor. I can feel the motor trying to grab but it’s not quite able to, it spins but the crank doesn’t move any faster. Here’s a short video of what’s happening when I use the throttle only. https://youtube.com/shorts/-ujgU_7KKN8?feature=share

Now I can tell you the moment it happened, I was walking the bike up a few steps and decided I’d use the throttle to help me - because why not I thought. After that I noticed the whining noise when pedalling and things quickly got worse from then on.

I replaced the sprag clutch thinking it must be that but it’s made no difference. I had a metal gear (not the blue nylon one) fitted to the motor at the time. I’m thinking because it didn’t fail here like the blue one might have, the stress has been transferred somewhere else in the motor and caused damage elsewhere, but I just don’t know where. I’ve also put the original blue gear back in just to rule out any chance the metal gear could be the issue. I can’t seem to find any reference to this same problem anywhere in the universe. Any help will be greatly appreciated, I’m out of ideas.
 
The TSDZ2 has 2 sprag clutches:
The "big" one in the main gear - that one engages when you push the padels. (When that one fails, your pedals slip, i.e. you can pedal, but the bike will not move)
And the "small" one inside the blue (or brass) gear: That one engages when the motor is supposed to push the bike.
(This is about the "older" TSDZ2 - non"B" Version)

So, with the above said, I would assume that your small clutch in the brass-gear is malfunctioning.
-> This clutch comes together with the blue / brass gear.
-> I would try to exchange the brass gear and see, if that helps. (Just re-read your post and noticed you did do that already....
I still think this area should be the problem - because:
Sometimes its only grease on the axis where the blue gear is sitting on that causes slipping.
Cleaning that area (and the spragclutch inside the blue gear) with i.e. alkohol fixes the problem also often:
There should be no grease in that area, otherwise the sprag clutch can not "grab" the axis.
Good luck!
 
Thanks for your response. I didn't realise the blue/brass cogs also had a clutch. What you're saying makes total sense when I look at the problem. I'll give it a good clean with isopropyl alcohol and post the result. Cheers!
 
So I cleaned the blue and brass gears inside and out thoroughly with alcohol, I also took out the helical gear shaft and gave that a good clean. I put the motor back together, tried it out on the bike but sadly it's doing the exact same thing with the noise and the slipping. I had the bike up in the bike stand and used the throttle to turn the motor. I started off in the low gears and it ran fine, I even had a smile on my face. But the more I progressed to the high gears the screeching noise and slipping returned, bugger. I've ordered a new helical gear shaft and a blue gear so I can rule those out those completely.

I don't know enough about the internal motor to point my finger at that for being the cause of the problem. I don't know if it's possible for components inside it to slip. ???. Meanwhile I'll need to wait a few weeks for the gears to arrive from China before I can progress. Whelp, better swap these casual clothes for some spandex, it's back to manual power again.
 
Thats a bummer.
I can not think of anything inside the motor to slip. Did you see any wear on the shaft when you cleaned it?
I would also buy these 2 parts as a next step. I think that area is the only possible one when it is a mechanical slippingvfailure.
Theoretically, it could also be an electronic failure: One of the Mosfets in the controller got marginal and that the motor does not get past a certain angle when that mosfet should be active when under load. But I never heard of such a failure.
 
The shaft didn't look like there was any significant wear, at least with my limited knowledge of worn out things. It certainly looks like something's been spinning around it though. I don't know what damage may have been done to the blue and brass gears, either way I can't imagine it would have been good for the shaft or the gear bearings as they were spinning with all that friction noise while I was troubleshooting the problem. IMG_6525.jpeg
 
Related question/problem: Is the TSDZ2 sprag clutch sensitive to cold temperatures? Mine is slipping this winter when riding in temperatures below about 20F (-7C), and has never slipped in temperatures above about 25F (-4C). When starting out from the bike being indoors it takes quite a while before it slips, but if it has been sitting out in the cold it slips right off. This is the "total frictionless spin slip", and fortunately, after a bit of spin and back and forth, it has always grabbed and I get home. But I am nervous now about riding at lower temperatures.
 
like Bafang, IF like your motor, have a spare.
Buy right and their cheap enough and far more sustainable than Bosch and their ilk. It's a great feeling when the bike goes down and you have the bits to have your steed back riding in an hour or two.

I know this goes against the grain especially when cash strapped, BUT oh the joy when I don't have to waitfor a kind soul on a forum to get me up and running. Ride now, sort the rebuild later. Even retired I still think my time has value. And riding is my freedom and self-care. I spend THOUSANDS less than a year maintaining a cage. $300-$500 waranty cost.
 
VTAllen said:
Related question/problem: Is the TSDZ2 sprag clutch sensitive to cold temperatures? Mine is slipping this winter when riding in temperatures below about 20F (-7C), and has never slipped in temperatures above about 25F (-4C). When starting out from the bike being indoors it takes quite a while before it slips, but if it has been sitting out in the cold it slips right off. This is the "total frictionless spin slip", and fortunately, after a bit of spin and back and forth, it has always grabbed and I get home. But I am nervous now about riding at lower temperatures.

It is, I have noticed the same, although it only happens irregularly and always resumes working. Might be that there's grease in the sprag clutch that gets too stiff when cold. For me it's been manageable so I haven't tried to fix it, but you could open the clutch, clean it with solvent and use better grease and only sparingly. Or get a better quality clutch straight away (it's a bit of work to change though as it's press fit to the main gear)
 
I'm curious to hear the noise, as I've got a "scronking" problem under load, but the YouTube link doesn't open for me. I've the same sound and behaviour as
and am awaiting a new clutch plus a new blue gear under warranty. Apparently the 'new' white gear that comes with the TSDZ2B eliminates the one-way needle bearing so I've ordered one hoping (in the absense of credible info) it might be a simple drop-in mod. Keep us posted. Good luck.
 
Here’s another link to the video, hopefully this one works for you

I too was wondering if the new type white gear would be a simple drop-in replacement, it would certainly help to eliminate this area as the cause of the problem I’m having.
 
I’ve just replaced the helical shaft and blue gear with brand new replacements. It’s no longer making the loud squealing noise but unfortunately the problem still exists. The friction is still there but without the noise. Something in the motor is grabbing eventually but not initially or when it’s under load. At first the motor spins faster than the crank until something is able to hold on tight enough to where the crank spins faster and catches up the the motor. At this point I’m very confused.
 
I’ve just replaced the helical shaft and blue gear with brand new replacements. It’s no longer making the loud squealing noise but unfortunately the problem still exists. The friction is still there but without the noise. Something in the motor is grabbing eventually but not initially or when it’s under load. At first the motor spins faster than the crank until something is able to hold on tight enough to where the crank spins faster and catches up the the motor. At this point I’m very confused.
That is really odd. My (last?) attempt would be to open the motor itself and check potential slipping between axis and coil-body (i.e. is this key in the right place - see picture)
 

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Here’s another link to the video, hopefully this one works for you

I too was wondering if the new type white gear would be a simple drop-in replacement, it would certainly help to eliminate this area as the cause of the problem I’m having.
Yes, that link worked and your screeching noise is nasty, and not like my scronking noise. I would say Olli is right when he diagnoses the needle one-way bearing inside the blue or brass gear, as your sprag clutch isn't doing anything in the video; it serves to isolate the pedals from the motor input. In my work I did once or twice get foxed when substitution of a part failed to remedy the prob, as the substitute was faulty too. Also when i put a brand-spanking new spark plug in my motorbike which I found was breaking down internally. So, possibly you have two knackered needle one-way bearings? I'll report back when the camel caravan arrives from China.
 
That is really odd. My (last?) attempt would be to open the motor itself and check potential slipping between axis and coil-body (i.e. is this key in the right place - see picture)
Well it looks like this was indeed the problem. I fitted a new internal motor this afternoon and the problem has gone away completely. I've pulled apart the old motor, which is only about 4 months old and is a supplier replacement for a faulty one I was initially given. With one hand I could hold the rotor with the magnets around it and turn the shaft with my fingers on the other hand, it's a little tight but I don't think should happen at all. Looking closely I can see a slot on the rotor and an opposing slot on the shaft but there's no key in between them locking them together - the shaft is moving independent of the rotor. I haven't pulled it apart completely because it's late and apparently I'm making too much noise but I'm confident that the cause of the slipping is a missing key locking the shaft to the rotor. Thank you for the info!
 
Well it looks like this was indeed the problem. I fitted a new internal motor this afternoon and the problem has gone away completely. I've pulled apart the old motor, which is only about 4 months old and is a supplier replacement for a faulty one I was initially given. With one hand I could hold the rotor with the magnets around it and turn the shaft with my fingers on the other hand, it's a little tight but I don't think should happen at all. Looking closely I can see a slot on the rotor and an opposing slot on the shaft but there's no key in between them locking them together - the shaft is moving independent of the rotor. I haven't pulled it apart completely because it's late and apparently I'm making too much noise but I'm confident that the cause of the slipping is a missing key locking the shaft to the rotor. Thank you for the info!
Good to know! Thanks for posting! Kudos to @endlessolli! I guess it's fixable if you can aquire a Woodruff key and slap it in there with some Loctite. Or a warranty claim.
 
Last edited:
The TSDZ2 has 2 sprag clutches:
The "big" one in the main gear - that one engages when you push the padels. (When that one fails, your pedals slip, i.e. you can pedal, but the bike will not move)
And the "small" one inside the blue (or brass) gear: That one engages when the motor is supposed to push the bike.
(This is about the "older" TSDZ2 - non"B" Version)

So, with the above said, I would assume that your small clutch in the brass-gear is malfunctioning.
-> This clutch comes together with the blue / brass gear.
-> I would try to exchange the brass gear and see, if that helps. (Just re-read your post and noticed you did do that already....
I still think this area should be the problem - because:
Sometimes its only grease on the axis where the blue gear is sitting on that causes slipping.
Cleaning that area (and the spragclutch inside the blue gear) with i.e. alkohol fixes the problem also often:
There should be no grease in that area, otherwise the sprag clutch can not "grab" the axis.
Good luck!
Hey endlessolli, this brass gear is new/ never installed afaik. Is the sprag clutch bearing (609RS) not working? It rotates freely in both directions as you can see it this video.

 
In blue or brass gear has 2 things in it: a simple roller bearing (which you show mostly in the video) and on the other side the one way bearing. To verify that that one works you need to test it on the axle, since the rollers in there ‚grab‘ the axle in one directin (and roll in the other direction)
 
In blue or brass gear has 2 things in it: a simple roller bearing (which you show mostly in the video) and on the other side the one way bearing. To verify that that one works you need to test it on the axle, since the rollers in there ‚grab‘ the axle in one directin (and roll in the other direction)
Thanks for that info. I pulled the blue gear out of the motor and it behaves the same way as the brass gear. Is there a diagram/ exploder view that shows how this one way bearing works?
 
For anyone with the tsdz2b with a similar clutch slipping problem....I had the same issue.
The motor would slip under load like uphill or when moving off after stopping.
I emailed pswpower and they originally said it was the torque sensor and sent me a new one.
I didn't think it was that because the torque sensor was kicking in just fine and I could hear the motor spinning just fine but there was limited power to crank. I changed that and problem remained.
They then said I should change the main gear and charged me $25 for postage and sent me that.
In the meantime the problem was getting worse so I opened the motor up and noticed excess grease on the plastic cover and a little on main gear. I took the gear out and sprayed some degreaser on both sides of the gear and cleaned the cover.
Put it back together and voila...all good.
Hasn't missed a beat since.
I now have a spare torque sensor and main gear too.
 
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