Stromer ST2 irregular assist issue

IanStewart

New Member
Hello all,

Edit. Perhaps this is similar to the power pulsing thread however that thread is in respect to an ST1 issue and this is for an ST2. Hence the new thread.

I bought an ST2 about 4 months ago and almost from the start I found problems with what I can only describe is a patchy assist. The problem has been getting worse so I took it in to the dealer and apparently they said they changed the rear torque sensor and the problem is fixed. But on the ride home from the dealer I didn't find any improvement at all.

Bought in Berlin from dealer Lautlos

Here is what happens:
In assist level 3 or any level- everything can be working fine. Then perhaps I might stop at traffic lights and the assist will not kick in at all as I try to pull away. I need to quickly change to another gear for the moter to activate or I just end up over the handlebars in a stall position. Secondly less dangerous but more annoyingly while you are riding the assist will just simply stop momentarily then start again. They whole time I'm giving the same amount of pedal effort (torque) to the bike. Looking at the screen I see the assist bar rise to a constant level and then it will simply vanish completely then reappear again coincidently with the physical irregularity that I've described while riding. So the electronics is also showing the irregular issue. I tried to film the bar on the screen doing this irregular dance but it was near on impossible. It's a patchy annoying uncomfortable ride sensation that simply does not make for a fun riding experience.

Now I can come out the house and the bike seems to perform well for 20-30km. Then after a stop the problems start. Or it can happen right from the start of the day with a full battery. I am seeing no link or connection to the issue based on battery capacity, charging or bike usage. It's completely random.

So the dealer has had my bike for the last 2 weeks. They gave me an ST1 as a replacement and I now have back the same faulty ST2. The ST1 is not as powerful or has the same range as the ST2, but it performs the same way every day and ride and give a steady smooth electric assist. Heck even my wife's 900 Euros electric shopping bike gives a smoother less problimatic ride that the ST2.

What I don't really know now is if I actually have a faulty ST2 or this is simply something that all the bikes do.

Any help would be extremely appreciated.

Ian
 
Last edited:

bluecat

Well-Known Member
"Lautlos" might not have time or experience to solve the problem. But you may support them.

Try riding in BOOST mode. This is slow, but no influence from pedaling .
Try to start at green lights with very low gear.
Tells you, if the hall sensor needs a whole turn.
Keep always all lights on. Are they flickering?
Take another battery. Is the BMS working fine?

If all remains without effect: Ask the dealer for a new controller.
 

IanStewart

New Member
"Lautlos" might not have time or experience to solve the problem. But you may support them.

Try riding in BOOST mode. This is slow, but no influence from pedaling .
Try to start at green lights with very low gear.
Tells you, if the hall sensor needs a whole turn.
Keep always all lights on. Are they flickering?
Take another battery. Is the BMS working fine?

If all remains without effect: Ask the dealer for a new controller.


Thanks bluecat,

I will try boost and lights. I generally alway anticipate stopping and move in advance to a low gear. Almost never start in highish gear so I don't think this is related to my problems. I won't consider buying another battery till I get working bike. Already 7k down on a unreliable system which is fairly annoying considering I've had the bike back at the dealer twice now.

What is a BMS? Please.

I just spoke to the dealer and while they recognise that there was an issue when I brought it in, to release it back in the same condition when some proper test riding could have shown them it wasn't fixed is somewhat strange. I now need to spend another afternoon returning it.

I hope it gets fixed because when it's working I love it.

Ian
 

Mark_0

New Member
I had exactly the same problem cycling away from a stop. And I found out that it has something to do with changing down gears as you prepare. Something must happen to the logic in the control system. So I gave up changing down as I came to a stop. And the problem disappeared completely. Very odd.

btw if it does happen (i.e. grinds to a halt as you pull away) just quickly change gear and it clears immediately.