If the chain keeps falling off, possibly because the transmission is too loose.
You can adjust the transmission by following the steps below.
- Shift into gear 7. Rotate the cranks forward and shift into gear 7, which should place the chain on the smallest cog.
- Tighten the barrel adjuster on the derailleur. Turn the barrel adjuster on the derailleur counterclockwise 1/2 to one full turn.
- Shift between all gears to test the alignment. Rotate the cranks forward with one hand and shift through the gears at the same time. Check to see if the derailleur moves the chain to each gear smoothly.
- Repeat the adjustment. Turn the barrel adjuster counterclockwise, 1/2 to one full turn at a time, and test the shifting. Do not turn the barrel adjuster counterclockwise all the way or the adjuster will come out of the threaded hole.
- If the issue is fixed, re-install the battery and test the bike thoroughly.
If there is still no way to solve it, please contact our customer support and send us a video which would help us better judge what problem causes it: email@example.com