The very first bicycles built were called penny farthings, because the big front wheel was huge (like an old fashioned penny), and the back wheel was tiny (like another coin used at that time, called a farthing).

The pedals were attached directly to the front wheel of the high-wheelers. The larger the front wheel, the farther the cyclist would travel with each turn of the pedals. This meant that they could go very very fast on the flat, but it was hard work going up hills!

If you want to look at a modern bike, the main difference you notice is that the wheels are the same size. This is because modern bikes use gears.

While the high-wheels were fast, they were also dangerous. The rider was very high off the ground and perched dangerously over the front wheel. The slightest obstacle in the road could result in a nasty fall on to the road. They had narrow tires made of solid rubber (which sometimes could roll off their rims), high-wheeled bicycles were designed for speed, not for safety.

These were the kind of bikes used by small children in Victorian times. They were tricycles, meaning they had three wheels, and wouldn't tip over. The boy on the left has a bicycle, with two wheels.

Imagine how difficult it would have been for the girls, wearing long skirts, to ride a bicycle like their brother!

Even the earliest bicycles used spokes of one sort or another. In fact, even in ancient times many chariots and animal-drawn carts used spokes. A spoked wheel can be made as strong as a solid one and have only a fraction of the weight. While early spoked wheels were almost always made out of wood, the bicycle wheels and spokes of today are made out steel or aluminum.

Why does weight matter? Each time you push the pedals, you have to accelerate the weight of the wheel both forward and around its center. You can see this when you ride--the front tire of your bicycle rotates while it moves forward along with you and the bike.