TSDz2 brass gear whining

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Btypark   10 µW

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TSDz2 brass gear whining

Post by Btypark » Jan 13 2022 11:08am

Hi All

Not sure if this is a common problem or maybe not even a problem but having changed to a brass gear cog, I cant help but be quite self conscious when I set off on my commute. The motor is properly loud for the first 5 minutes under any significant load. Lots of torque initially which seems to then dwindle slightly along with the whirring/humming sound. Thereafter I'm pretty sure I'm not getting the full motor power for the rest of the journey (10 miles)
Same issue happens from every cold start. Does anyone have an insight into what might be going on here? More grease necessary? Something else I cant think of or should be looking for?

Thanks guys!

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Alfie   1 W

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Re: TSDz2 brass gear whining

Post by Alfie » Jan 13 2022 7:32pm

My brass gear is noisy until it warms up. Especially on a cold morning. Not noticed any lack of power though.
Whyte T129 TSDZ2

Btypark   10 µW

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Re: TSDz2 brass gear whining

Post by Btypark » Jan 14 2022 4:53am

Interesting. Can I ask though - is it noisy enough that people in the street will turn around to find the source of the high pitched whine?!

Hillhater   100 GW

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Re: TSDz2 brass gear whining

Post by Hillhater » Jan 14 2022 5:33am

Btypark wrote:
Jan 14 2022 4:53am
Interesting. Can I ask though - is it noisy enough that people in the street will turn around to find the source of the high pitched whine?!
Well, mine is for sure !....but it was with the blue gear also .
Also my roller clutch in the brass gear just destroyed itself, so i replaced it, regreased all gears, ...and it still whines !
I suspect it is the motor/controller ?
This forum owes its existence to Justin of ebikes.ca

Btypark   10 µW

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Re: TSDz2 brass gear whining

Post by Btypark » Jan 14 2022 5:55am

Maybe... I just wondered why the noise on my motor dies down along with the torque assist. Perhaps it's more psychological than real but it definitely feels less oomph (technical term) Than my Bosch sport cx bike over prolonged usage

Hillhater   100 GW

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Re: TSDz2 brass gear whining

Post by Hillhater » Jan 14 2022 6:24am

The reduction in power (omph ) is likely the result of battery voltage drop..( sag under load ,and voltage reduction as capacity is used) .
How much this is noticed will depend on the individual battery spec, capacity, chemistry, age, etc etc.
A fully charged pack will feel more “pepy” initially than it does after that top 5% of capacity is used.
The volt drop with Capacity reduction is not linear , with the first 5-10% of voltage dropping much faster than the next 20%.
This forum owes its existence to Justin of ebikes.ca

Btypark   10 µW

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Re: TSDz2 brass gear whining

Post by Btypark » Jan 14 2022 8:01am

This makes sense. Its a high capacity battery but it's made up of Chinese cells. Short of stopping and recharging to the max every two miles I guess it's something to live with. :cry:

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Alfie   1 W

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Re: TSDz2 brass gear whining

Post by Alfie » Jan 14 2022 8:28pm

Btypark wrote:
Jan 14 2022 4:53am
Interesting. Can I ask though - is it noisy enough that people in the street will turn around to find the source of the high pitched whine?!
No it’s not that noisy. The original nylon gear was absolutely silent.
Whyte T129 TSDZ2

Btypark   10 µW

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Re: TSDz2 brass gear whining

Post by Btypark » Jan 17 2022 5:16am

Hmmm - something not right then - I guess I need to open her up an have a look inside... :o

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Alfie   1 W

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Re: TSDz2 brass gear whining

Post by Alfie » Jan 17 2022 7:23pm

What software are you running? I found when I installed the Mbrusa software there was a marked improvement in motor noise.
Whyte T129 TSDZ2

fletchro   1 µW

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Re: TSDz2 brass gear whining

Post by fletchro » Mar 13 2022 2:39pm

I worked at a gear manufacturing company. I took a course on detailed gear design. Noise was one of the topics. We didn't study it in depth, but I remember several factors that influence noise. They are ratio, pitch, and face contact ratio. Really high ratios (as found in the TSDZ2) are bad (partly because they reduce the face contact ratio). Also, ratios that are very close to integers are bad, like a gear set with almost exactly 1:2 ratio. We should also include pressure angle if we're talking about pitch. You can make a gear set quieter by changing the ratio slightly or making it wider (face contact ratio). But here's the main takeaway: unless you are designing the gear set (and the container for it), there's almost nothing you can do about gear noise. After it's designed, all you can do is keep it properly lubricated. You have noise because metal is touching metal at a certain frequency == sound. The plastic gear is quieter because it absorbs some vibrations as it hits. 🤷‍♂️ Sorry. You will probably always get more noise with the brass gear.

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