If the transmission is too tight/loose, you can follow these steps:
1. Shift into gear 7. Rotate the cranks forward and shift into gear 7 which would place the chain on the smallest gear.
2. Loosen the barrel adjuster on the derailleur. Turn the barrel adjuster on the derailleur clockwise to 1/2 to 1 turn to release it.
3. 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 if the derailleur moves the chain to each gear smoothly.
4. Repeat the adjustment. Turn the barrel adjuster clockwise, 1/2 to 1 full turn at a time, and test the shifting. Do not keep turning the barrel adjuster counterclockwise or the adjuster will come out of the threaded hole.
If the issue is fixed, please reinstall the battery and test the bike. If the issue still exists, please contact us for help: firstname.lastname@example.org