Controller type

Victor F

New Member
I recently got a W class and I love it but my pedal assist cuts out nearly instantly after the torque decreases. This happens while pedaling even if my stroke lessens even a minor amount. I would like to find out exactly what controller our bikes use so i can learn more and possibly make the motor taper off more slowly.

Secondly my chain rubs against my chain guard some in 7th gear. Does anyone else have this? How did you address it?

Lastly, my fenders I think are adjusted properly but sometimes i think my tire is rubbing on the fender wire attachment piece. Has anyone else experienced that? Mine seems minor and infrequent.


New Member
Hello Victor,
I have an N-Class 250W model but the differences may be small enough to help.

For the pedal assist cutting out you may want to try a higher assist level or a different gear. I personally find the controller very smooth, on my bike it does not cut out (like it would when actuating the brake levers a little bit, just enough for the switch to work) but insted decreases the power.
Or in other words, decreased pedalling results in decreased assist, but not abrupt. Maybe the controller or torque sensor has developed a problem. I had similar problems and contacted Nora from Ariel Rider support, and they sent me reasonably priced replacement parts which fixed that issue. On which assist levels do you experience the cut-out?
I have some pictures of the controller at home and from memory there was a brand name on it. I will check and come back if I find something there.

Chain rub: The chain guard is mounted on some quite soft metal brackets on my model, is it not possible for you to bend it outward a bit?

The fenders have a VERY tight fit with the original CST tires, which is why the light cable routed inside the fender was damaged on my bike. It is so tight that too high tire pressure does result in tire rubbing. I rerouted the cables to run alongside the fender stays, thus eliminating the problem. My next tires will be Schwalbe Big Ben Active, which are a bit smaller (2.15 istead of 2.35), that should give more clearance and still look nice.


Victor F

New Member
Thanks Andy.
I'm experiencing the cutout on assist level 6 and have not tested on lower levels. I believe it may just be a setting issue. I know the controller is Dapu brand but nothing more.

I believe my front springer fork is still slightly too tight and is reducing my fender clearance. I will try adjusting that first.

I will try just moving the guard out slightly. That should fix the issue of chain rub.