26inch 7 speed fat tire electric bike with middle drive motor 

1. Check the tightness of the chain before the electric bicycle is used. The chain is too tight when riding on the ankle. If it is too loose, it will easily vibrate and rub against other parts. The sag of the chain is 1-2mm, which is suitable, and can be properly adjusted when riding without the ankle. When the chain is adjusted, first loosen the rear wheel nut, and then screw out the left and right chain adjustment screws evenly to adjust the chain tightness and retighten the rear wheel nut.
2. The lubrication of the chain should be checked before using the electric bicycle. Feel and observe whether the chain chain of the chain is flexible or not, and whether the chain rust is serious. If the corrosion or rotation is not flexible, the right amount of lubricant should be added, and the chain should be replaced seriously.