I bought an Addmotor H-1 Platinum on June 17th of this year and received it about a week later. Since new it has thrown the chain off the front sprocket when rolling backwards or riding over rough terrain and shifting up or down in the first four gears. I spent lots of time online trying to find out why it was doing this and making sure the cassette and derailleur were working properly and correctly adjusted. I contacted Addmotor support and they had me send numerous pictures and videos of the problem and gave me a few things to do and check, none of which helped. It was very obvious from the beginning that there was a serious alignment problem between the front sprocket and the cassette, but I was puzzled how this could be. Then I measured the distance between the crankshaft center and the rear axle on both sides using a variety of methods that included a plumb bob, a five foot long straight edge, and various right-angle squares. It turns out the axle on the brake side is 6-7mm closer to the crank centerline then the cassette side. The offset matches what you see at the front sprocket in terms of misalignment. I’m a former professional motorcycle mechanic (and instructor) and have a lot of experience checking alignment problems on frames. Addmotor refuses to admit there is a defect in the frame and insists that the problem is caused by “shifting while pedaling backwards” (sic). This whole process has gone on for a month, and involved phone calls to Addmotor as well as the emails, etc, mentioned above. Today I filed a complaint with California Consumer Affairs and the El Monte BBB. Does anyone have any advice for me? I’ve told Addmotor they can refund my money, give me a new bike, or pay a local bike shop to install a new frame.