Jerky PAS


New Member
Hi rear-hub-motor-cadence-sensing-pas users. Has anyone of you experienced a 'jerky pedal assist' output?

I have logged 6000+km already, riding my bike to work everyday since the pandemic. The commute is about 7km flat + 7km uphill. It was smooth.

I noticed the jerky behavior (only on ascent) starting yesterday when I installed a rear rack to place my everyday carry (heavy) backpack. Today, I wear back the backpack, like I always do since day one, to see if the load balance was the culprit. No. The motor still gives a sudden jolt of power every now and then during ascent.

I'm not losing power. Instead, I am getting a jerky increase in assistance. I used to climb on PAS 3 (60% power) at 13kph ave speed. Now, to compensate for the jerkiness, I climb at PAS 4 (80%) at 22kph. The jerky behavior feels like you're bumped from behind. Not cool.

I stopped to feel the motor. It didn't give off an abnormal heat nor a weird noise while climbing.

I guess the problem is not mechanical, but electrical?

I will check later using throttle-only while climbing to see how it behaves.

Any leads will be appreciated. Thanks.