Bosch CX Gen3 Harsh Low End Engagement

nachodate

New Member
Region
USA

We recently bought a Yuba Supermarche, which has the Gen3 bosch CX motor, and have noticed that the low end motor engagement is pretty harsh. It's very noticeable when the motor engages and disengages, and at low speeds, its constantly clicking on and off in a jerky way and kinda ruins the ride. My previous bike had the shimano STEPS motor and engaged much smoother.

The CX Motor Firmware is 1.8.0.0. I know that the current version is 1.8.6.0, and I've seen a few people mention that one of the updates makes the top end fade better, rather than hitting the wall at 20mph, but does anyone know if any of the firmware updates between 1.8.0.0 and 1.8.6.0 help soften the low end engagement too? Or is anyone else experiencing this harsh low end engagement? I'm reluctant to update the firmware, cuz I have a tuning chip that I don't want to cause problems for (the harsh engagement was happening before I installed the chip), but I would risk upgrading if the 1.8.6.0 includes a patch to soften the low end engagement.

Thanks for the help!
 

Mike TowpathTraveler

Well-Known Member
Since I have an older Yamaha PW drive on my Haibike, I won't be of much use. E-Mountain Bike Magazine (online) had an article on the latest Bosch firmware update, but that was for the Gen 4 line up of motors, so it does not apply here.

I do wonder if you have a torque sensor issue ongoing here. Comparing how the Bosch feels compared to what a Shimano or a Yamaha or other mid drive does in starting out might not apply here. And I believe the only way to find out, is by having a qualified Bosch technician check for faults within your system. Motor engagement at low rpm is relatively a smooth transition in these high tier motors.

But that's a possible problem, isn't it? You chipped your motor. At a minimum, to take it in for service and possible warranty claims, you have to remove that chip. Hopefully somebody here can tell you if the chip left any clues for their diagnostic tools to pick up. Good luck and let us know how it works out for you. That's a cool looking and very practical minded cargo bike!
 

Ravi Kempaiah

Well-Known Member
which has the Gen3 bosch CX motor, and have noticed that the low end motor engagement is pretty harsh. It's very noticeable when the motor engages and disengages, and at low speeds, its constantly clicking on and off in a jerky way and kinda ruins the ride.

That particular bike has Gen 2 Bosch CX motor.
The torque sensor on the Bosch system is very robust and they don't go out of calibration but very occasionally it may.
Also, please check if your spoke magnet is positioned correctly.