Simple bicycle is not so simple | The Daily Texan

Physicists are known to tackle the big problems: How did the universe originate? What is the nature of matter, energy and time? How can we make the rules that work for very small objects (quantum mechanics) not conflict with those that work for very large ones (general relativity)? However, one doesn’t need to reach for such abstract material to find topics that physicists struggle to understand. In fact, you need look no further than right outside your classroom at the common bicycle.
This seemingly simple device, which has existed in its current form for more than a century, is devilishly complicated and there still isn’t a fully intuitive explanation of how it balances on its two wheels.
What makes the question of the bicycle’s stability so perplexing is that the answer seems immediately obvious. It’s stable because somebody’s steering it, right?

Not quite.
A bicycle remains upright even if the user removes his hands from the handlebars, effectively giving up his ability to steer. In fact, a bicycle doesn’t even need a rider at all: bicycles balance perfectly fine without anybody on them, provided they’re moving fast enough (somewhere between eight and 13 miles per hour — a relaxed speed).
A second explanation may come to mind, for those who have learned some high school physics: the spinning wheels keep the bicycle from falling.
Rotating objects, like the wheels of a bicycle, are stable and the faster they spin, the more stable they become. This gyroscopic effect, as physicists refer to it, explains why tops and yo-yos behave the way they do.

Simple bicycle is not so simple | The Daily Texan