Bosch CX motor anti-spin

[Deere John]

Hi, anyone know how CX drive delivers the power when you ride in bad grip conditions? It seems it have some kind of anti-spin feature. Example:

Now on these snowy days I have often come to some uphill with bad grip. If I ride on high assist mode it's very difficult to come up because it spin. But it just doesn't spin freely it kind of staggers, "Uh-uh-uh-uh-uh" kind of. It makes it very difficult to get somewhere because you can't modulate the power needed. If you run on eMTB mode you can otherwise modulate a little.

I guess it staggers like this to prevent free spin, something like a simple "anti-spin" feature. But I would rather have it work like regulating power/speed, no staggering, just easy going instead. But I guess that would be very difficult to implement.

 

[Gringo]

I stand to be corrected but I don't think there's anything clever going on in the controler

Thinking about it logically.
The amount of motor power is proportional to the torque on the pedals,

so as the wheel starts to loose grip there's no load on your pedals and torque sensor, so the motor cuts power,
without motor power you regain a little grip and put more pressure on the pedals so the motor starts up again, now there's extra power from the motor and the wheel looses grip, as the wheel starts to loose grip there's no load on your pedals and torque sensor, so the motor cuts power,
without motor power you regain a little grip and put more pressure on the pedals so the motor starts up again, now there's extra power from the motor and the wheel looses grip, and there's your uh,uh,uh,uh

 

[Deere John]

...hmm, yes maybe like that, because it is more eager to happen when riding just a little too high gear. Switching to a lower gear so I can pedal faster makes this phenomenon a little better.

 

[Benjahmin]

Go full Clarkson !
Spin the wheels and to hell with tyre wear

 

[Woosh]

Now on these snowy days I have often come to some uphill with bad grip. If I ride on high assist mode it's very difficult to come up because it spin. But it just doesn't spin freely it kind of staggers, "Uh-uh-uh-uh-uh" kind of. It makes it very difficult to get somewhere because you can't modulate the power needed. If you run on eMTB mode you can otherwise modulate a little.

I had a chance to test ride in the same snow, on the same route last week on two fat bikes, one with torque sensor and no throttle, the other with rotational sensor and throttle. I found what you described, both climbed alright, just that I felt more secured on snow using the throttle to override the sensors, even on flat roads.

 

[Deere John]

I had a chance to test ride in the same snow, on the same route last week on two fat bikes, one with torque sensor and no throttle, the other with rotational sensor and throttle. I found what you described, both climbed alright, just that I felt more secured on snow using the throttle to override the sensors, even on flat roads.

yes on my other eBike with Kunteng-controller and PAS-sensor I handle these situations easier because I just set a suitable assist level and it's always on as long as I just pedal. Funny, one other advantage with the DIY-kit