They can't help. My friend sells second hand bicycles recovered from the police. A couple of weeks ago they gave him an e-bike. This thing had been modified wit

They can't help. My friend sells second hand bicycles recovered from the police. A couple of weeks ago they gave him an e-bike. This thing had been modified with a twist throttle, 1 kW motor and a maximum speed of 62 MPH. He took it up to 40 MPH (on his own private land) before chickening out. The chain would simply not stay on the cassette at that speed. He reckons that if you did drive it to the limit, you'd go through a brand new set of disc brakes and calipers in a week, if you didn't manage to boil half the hydraulic fluid off in the mean time! But to a non expert this thing looks exactly like a regular bicycle--because it is (or was, before it was illegally modified to be a motorbike).