Does this video prove that most people don't know how bikes work?

What does it mean to ‘know how a bike works’? 

You might flatter yourself that you can ride a bike perfectly well – but is that really sufficient for claiming with confidence that you know how a bike works?

Not to put too fine a point on it, but there is a large difference between procedural knowledge and propositional knowledge – for instance, pretty much everyone knows how to use the past participle, but far fewer actually know what that means/refers to.

(In English, it's words typically ending in -ed: looked, defeated, cycled, etc.)

So we were more than a little interested when we came across this video claiming, not only that most people don't know how bikes work, but that they've also got a test to prove it.

If asked 'how do you make a bike turn left?', most people would likely reply with 'you turn the handlebars to the left' or – if travelling at a sufficiently high speed – 'you lean the bike to the left'.  

But that's not all there is to it.

The more self-reflective – or those who have risen up through the youth ranks – would be aware that in order to turn in one direction, first you have to counter steer in the other direction. 

It's something that everyone does – even if you weren't aware of doing so. To prove this, Derek Muller of Veritasium modified a bike so that the handlebars could be locked-out and only turn in one direction.

It very quickly becomes apparent that it's essentially impossible to turn left without first counter steering slightly to the right – but why is this?

The explanation is most intuitive if we first take a different example. Imagine balancing a broom in your hand. If you were to suddenly move forwards, the broom would simply fall backwards and onto your shoulder.

But if you were to make a slight backwards motion first – and get the broom leaning slightly in a forwards direction – then you would be able to walk forwards with the broom without it toppling over. 

Essentially the same thing is happening when you turn left or right on a bike. First you have to counter steer slightly in order to shift your centre of gravity so that you can make it around the bend.  

Derek goes into much more detail in his video, as well as going on to explain why it is that bikes don't need a rider to stay up right – suffice to say, it's a lot more than just gyroscopic action.