Why don’t you fall over while cycling?

Answer

A bicycle falls over due to the presence of gravity. When the bike is stationary, it is of course very good to feel. In theory you can just balance your bike: if you put the center of gravity of the bike just above the contact with the ground. However, this is not so easy to achieve in practice. It’s just a very unstable balance, and the slightest deviation makes the bike fall over.

When you ride a bicycle, the following happens:
If you have an imbalance in your balance, your bike will fall, the same way it falls when stationary. However, the bicycle will not fall if the handlebars react in the right way. If your bike is about to fall, steer the bike under you again.
For example, if you threaten to fall to the right, steer to the right. As a result, you will describe a bend to the right. Due to the fact that you go through a bend, you experience a centrifugal force (= centripetal force), which in this case is directed to the left. This centrifugal force counteracts the falling movement, so you come back upright.
Chances are you’ll overcorrect a bit, and then fall to the left. You steer to the left, and the centrifugal force brings you back upright. That way you stay busy all the time.

So when you ride a bicycle, you are actually falling all the time. If you’re driving very slowly, you may need to do some cornering to stay upright. However, if you go faster, the corners become much less sharp to get the necessary stabilizing centrifugal force. The faster you go, the slower you fall, and the greater the radius of the circular arcs your path describes.
Only when you go infinitely fast, your path is ‘infinitely straight’. A bicycle never goes perfectly straight. Try to lock your handlebars, so that you have to go straight ahead, you will quickly come into contact with the earth in a rough way.