BMX (it stands for Bicycle Motocross) bikes started in California in the lates 1960s/early 1970s, when motocross fans who didn't have, or couldn't afford, motorbikes started to race their own push bikes on dirt tracks. Soon, special tracks were built for the BMXers, official organisations were formed to run and BMX races and a new sport was born.
BMX bikes come in three different forms: BMX, Freestyle and Jump. Simply put, BMX bikes are race bikes, lightweight and perfect for off-road, with knobby tyres and a strong rear brake.
Freestyle bikes are designed for stunts and tricks, with sturdy frames and tyres suited to pavements and skate parks. They come with rotors or detanglers to keep the brake cables from getting caught up in the spinning handle bars.
Jump bikes (sometimes called Dirt Jumpers) are a mixture of the two, with a sturdy frame, knobby tyres and BMX wheels. Ideally suited to off-road or stunts, they come equipped with heavily treaded tyres and often no front brakes.