Poorest of quality components, not built to last
I bought a NIU NGT Pro, after 2 years and only 2k miles the main motor gave up. Managed to get one under warranty through the dealer in London (if it hadn't been covered it would have been £1000) a year on from that, and three years after purchase the bike is falling apart. The paint has flaked off the main arm, the kick stand and body of the brake callipers are rusting. Every so often, it will not start and I have to disconnect both batteries and then its ok. Random error codes flash when driving and you also have to pay £35 a year after the first 3 years to access the app. The longevity of the parts and components is far from what is expected. Very very poor Chinese components around a bosch motor. Aftersales support is not interested, I contacted Niu about the paint flaking off and they claimed it was a "feature". Don't go with this brand, it wont last more than three years if you are lucky.