The best thing you can do with a mountain bike is ride it. Having fun is number one. But when you start getting serious and identify little things you want to change, or when you want to buy a new bike, you start to realise that a mountain bike is a complicated beast made up of a lot of component parts. With this guide, we hope to show you those parts, and give you an idea of what they do and what makes a good one- taking the mystery out of buying and improving your bike.