The chain often falls off the flywheel or sprocket during the normal cycle of an electric mountain bike. This failure is called the drop of the chain
If the rear wheel is no longer in position and the chain is still loose, the chain should be cut short and then adjusted.
The sprocket, chain and flywheel are not on the same plane.
Sprocket appears axial beat (that is, left and right wobble). Elimination method: adjust the axial runout of sprocket.
Chain pitch is elongated to make it meshing with sprocket or flywheel. Remove method: 1 replace new chain / 2 renovate old chain with elongated pitch.
Chain pitch is elongated to make it meshing with sprocket or flywheel. Remove method: 1 replace new chain / 2 renovate old chain with elongated pitch.
Wear sprocket or flywheel teeth to make them meshed with chain. Elimination: replacement of sprocket or flywheel.