What Is a Bicycle?

Multiple gears (speeds) allow the rider to maintain a constant level of effort under changing conditions.

For example, they make it easier to pedal when climbing a hill.

They also make it possible to go faster, without pedaling faster.

That depends. Where do you live? How strong are you? How hard are you prepared to work?

The number of speeds a bike has does NOT determine how fast you can go.

A 24-speed bike is not faster than a 21-speed bike simply because it has more gears. It may even be slower.

More gears means more choices. Fewer gears means fewer choices. Period.

As the name implies, single speed bikes have only one "gear" – you cannot shift. So when the going gets tough, the only choice you have is to pedal harder.

Some single-speeds have a "flip-flop" hub, meaning they can be ridden either freewheel or fixed.

Fixed gear bikes ("fixies") are single speeds where the position of the rear cog is "fixed" relative to the rear wheel.

Or in English: if the wheels are turning, the pedals are turning. You cannot pause, coast or glide. Ever.

• You pedal slow, you go slow
• You pedal fast, you go fast
• You pedal backwards, you go backwards
• You stop pedaling, you stop

What's the appeal? They're a helluva a lot of fun. While they take a little getting used to, they have their advantages – and disadvantages.