Tongsheng Autopsy - Need Input

appaholic · Jul 23, 2024

Please see below & attached pic. Has anyone encountered similar?

I've moved on from Tongsheng to ToSeven & Bafang. But i wanted to open up my ild TSD's just for learning purposes and found this mess. My questions:

What is the gold / copper dust in the motor?

What causes it?

What do I do to avoid in future?

Mongo · Jul 23, 2024

My guess would be that you have an aftermarket brass reduction gear being chewed upon by the rotor's steel gear, causing metal flake mayhem.

appaholic · Jul 23, 2024

Mongo said:
My guess would be that you have an aftermarket brass reduction gear being chewed upon by the rotor's steel gear, causing metal flake mayhem.

I don't think so....can't find any damage on brass gear and i got from Ecocycles when I originally ordered years ago.

A-DamW · Jul 23, 2024

Well, those flakes are coming from somewhere!
Maybe a worn thrust bearing is allowing the brass gear to come in contact with the case or something?

A-DamW · Jul 23, 2024

And what is that? looks like a gear tooth.

Zambam · Jul 23, 2024

Look at the profile of your brass gear teeth compared to a new one Metal Gear Replacement for Tongsheng TSDZ2 Mid Drive Motor Upgrade Part - New | eBay . Yours look badly worn. The bearings probably worn also. What were the symptoms?

appaholic · Jul 23, 2024

Okay, I see everything you guys were talking about....this is from last summer and I've got two motors....can't remember symptoms on this one specifically.

You guys have sold me. So what would cause this scenario in your opinions?

appaholic · Jul 23, 2024

Zambam said:
Look at the profile of your brass gear teeth compared to a new one Metal Gear Replacement for Tongsheng TSDZ2 Mid Drive Motor Upgrade Part - New | eBay . Yours look badly worn. The bearings probably worn also. What were the symptoms?

A-DamW said:
Well, those flakes are coming from somewhere!
Maybe a worn thrust bearing is allowing the brass gear to come in contact with the case or something?

What is a thrust bearing? Why would it be worn? Is heat part of the problem? Just trying to gain some knowledge from more experienced folks...

appaholic · Jul 23, 2024

Zambam said:
Look at the profile of your brass gear teeth compared to a new one Metal Gear Replacement for Tongsheng TSDZ2 Mid Drive Motor Upgrade Part - New | eBay . Yours look badly worn. The bearings probably worn also. What were the symptoms?

If it's the motor I'm thinking of, the symptoms were....working great, hit a hard bump into a steep short uphill. I immediately heard grinding & winding....assumed it wasa spragclutch...

Guerney · Jul 24, 2024

Some brass alloys are self-lubricating, which is why many locks are brass - whoever manufactures these brass gears must have considered the puny ickle TSDZ2, and reasoned strong steel wasn't necessary.

Zambam · Jul 24, 2024

appaholic said:
If it's the motor I'm thinking of, the symptoms were....working great, hit a hard bump into a steep short uphill. I immediately heard grinding & winding....assumed it wasa spragclutch...

What's the history of the motor? Miles ridden? Kind of riding? Did you install the brass gear yourself? I believe TSDZ2 came with a blue nylon gear from the factory. Did it have a brake cutout sensor?

appaholic · Jul 24, 2024

Zambam said:
What's the history of the motor? Miles ridden? Kind of riding? Did you install the brass gear yourself? I believe TSDZ2 came with a blue nylon gear from the factory. Did it have a brake cutout sensor?

I installed the brass gear replacing the blue gear. It did not have brake cutout sensors. I've ridden less than 200 miles on city streets, greenways & gated fire roads / 2 track dirt roads. No single track trail riding nor extreme environments. No temp sensor.

Zambam · Jul 24, 2024

appaholic said:
I installed the brass gear replacing the blue gear. It did not have brake cutout sensors. I've ridden less than 200 miles on city streets, greenways & gated fire roads / 2 track dirt roads. No single track trail riding nor extreme environments. No temp sensor.

That's surprisingly few miles to have a new motor fail. Was there a problem with the blue nylon gear that made you change to brass?

appaholic · Jul 24, 2024

Zambam said:
That's surprisingly few miles to have a new motor fail. Was there a problem with the blue nylon gear that made you change to brass?

No, just changed based upon the failure rate of blue gears discussed in past. Im a big guy, so assumed if others were experiencing failures, it would be prudent for me to practively upgradr.

Zambam · Jul 24, 2024

appaholic said:
No, just changed based upon the failure rate of blue gears discussed in past. Im a big guy, so assumed if others were experiencing failures, it would be prudent for me to practively upgradr.

So you never rode on the blue gear? Were you shifting properly, starting from a stop from low gear incrementing to high? Don't know if could be an issue with your's, but I've seen instances when I did not have brake sensor, and still have weight on the pedals, bike hasn't come to a full stop and power still shows it being delivered on the display, which means the motor was working against the brakes. After that I promptly installed brake sensors.

Mongo · Jul 24, 2024

With that amount of riding time (less than 200 miles), and if the brass gear was out of machining tolerance, I'd think the rotor steel gear could chew it up right quick - especially if that sliver @A-DamW pointed out is a broken-off tooth.

So, to make it rideable, I'd clean it up thoroughly, then reinstall the blue nylon gear. I'd also check elsewhere for those conductive shards. Dunno about that top bearing, which I thought stayed in the casting normally - I hope it isn't bound up.

I guess there was never a PEEK plastic gear developed for this motor?

appaholic · Jul 25, 2024

Zambam said:
So you never rode on the blue gear? Were you shifting properly, starting from a stop from low gear incrementing to high? Don't know if could be an issue with your's, but I've seen instances when I did not have brake sensor, and still have weight on the pedals, bike hasn't come to a full stop and power still shows it being delivered on the display, which means the motor was working against the brakes. After that I promptly installed brake sensors.

I'm sure I wasn't every time. I'll never make that claim. But i try to be cognizant of this practice. My wife is horrible about starting out in a high gear & have never had an issue with either of her motors (350W & 500W). But she's also 80lbs lighter.

Zambam · Jul 25, 2024

appaholic said:
I'm sure I wasn't every time. I'll never make that claim. But i try to be cognizant of this practice. My wife is horrible about starting out in a high gear & have never had an issue with either of her motors (350W & 500W). But she's also 80lbs lighter.

I try to be gentle and not beat on the motor. On level ground from standstill, I don't start on the lowest gear either. I'd start on gear 3 or 4 but apply light pressure on the pedals to get the bike rolling first before more pressure to get up to speed. As you know, my TSDZ2 came to me with a broken casing where I transferred the guts over to a new casing. The box of parts the motor came in had a new brass gear in it but I elected to keep the blue nylon gear to keep it stock as much as possible (only change was the additional bearing on the axle- drive side for extra support). Motor currently has 550 miles, running fine so far- knock on wood.

Tongsheng Autopsy - Need Input

appaholic

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