bergerandfries wrote: ↑
Aug 28 2019 8:43pm
feketehegyi wrote: ↑
Aug 27 2019 1:48pm
mgtroyas wrote: ↑
Aug 27 2019 10:06am
I've been enjoying my TSDZ2 daily on my classic 90s steel 26" MTB for more than a year now, for daily commuting. It's a great motor. But a problem has slowly arised and now it's becoming frustrating. I hope somebody cand point what the origin could be. It's the 2018 350W 36V model with xh18 controller and no brake sensors. I use it with a 36V 20Ah battery.
Hello, sounds like problem with main gear - sprag clutch bearing. The problem on mine was not visible, but after I replaced it's been felt again as a new motor.
Blue gear should be also checked. That's visible if blue gear has problem.
I have videos how I replaced both of them on my youtube channel.
I have the same, very rare issue. Do you know the mechanism for the sprag clutch bearing failure causing this? Is it kind of like a positive feedback loop where the sticking bearing continues to apply torque to the shaft and the torque sensor senses torque even though the rider isn't applying pressure to the pedals?
Thanks feketehegyi for pointing to the main gear - sprag clutch bearing, initially I only thought about the nylon gear.
So the problem is located on one of the two sides of the motor: right side (sprag clutch) or left side (blue gear). I didn't want to blindly open both and replace parts only to notice it's not being solved (also I only have a blue gear replacement). So I started thinking about it.
The axis on my motor has some milimeters of play, if I grab both pedals and press one up and the other down I can sense it (a local store pointed me to it). Perhaps something is being compressed too much on heavy starts due to that play, then the sudden change of torque plus the friction makes the sensor think the opposing fore is huge and triggers maximum response.
Right side gear is made of iron and has a bearing, left one is nylon and is open, probably the right side will be stronger, less prone to deformation and play. So perhaps depending of the leg is applying force, I'm mainly pressing one part or the other. Will be a difference if I start pedaling strongly with the right leg?
Guess what? It does! 100% of the times I do the first pedal with the right leg, the motor doesn't choke. Tested on two 30min commutes. What a lovely feeling having a trustworthy motor again! So the conclusion I reach is my blue gear is somewhat damaged, starting pedaling with the left leg presses the axis and gear to the other gears and increases friction, starting pedaling with the right leg solves the problem. I'll wait to see the evolution of things but if it works this way I'll wait longer to change the gear, as once engaged, the motor works flawlessly.
So in brief, from my experience:
- Never start from stopped position on long gear, specially on hills. Start on short gears and pedaling gently the first second until the motor revs up.
- When shifting to higher gears, reach a high pedaling cadence before, and relax pedaling during shift, then engage gently to avoid sudden difference in torque.
- Try to always hard start preferably with right leg as that's the stronger part of the motor internals¿?
- If some internal damage is already done, you'll sense some millimiters play on the axe, when grabbing both pedals and twisting it.
- In that case start pedaling from stop with left and right legs to determine which side the broken part is.
- In that case always hard startingwith right leg could solve your problems as that's the stronger part of the motor internals.