Question: Does it fit all hoverboards?
Answer: No, it only fits hoverboards which central shaft girth is less than 9.8in. Also the central shaft shape must be round or oval. If you don't know your hoverboard's girth and shape, please don't buy it.
Question: Will it be as tight as soldered to a hoverboard?
Answer: No, it will not. It relies on iron ring and screws to mount on the hoverboard, and if you shake it hard, it will still come loose.
Question: With this handlebar, will the rider fall over?
Answer: Yes, the rider can still fall over. The handlebar just provides extra support, and once the gravity center of body is unbalanced, people will still fall over.