BMX bikes are distinctive for their small frames, minimalist features, and mostly 20″ wheels. Originally designed for tween’s and teen’s competition on dirt tracks simulating motorcycle MotoX, the bikes became a staple for kids from 7 years-old, even into their 20’s.
As with other bicycle categories, inventive riders and makers have come up with many other uses for BMX bikes. With each use, modifications were needed to optimize the performance in that part of the sport. Today, there are BMX bikes specifically designed to fit the following Vert, Park, Street, Flatland, BMX freestyle all.
Dirt jumping is one of the names given to the practice of riding bikes over cement type jumps of dirt or soil and becoming airborne. The idea is that after riding over the ‘take off’ the rider will become momentarily airborne, and aim to land on the ‘landing’.
Dirt jumping can be done on almost any vehicle with wheels, but it is usually executed on a dirt jump bike.
BMX bike built for dirt jumping tends to have a longer top tube than a street BMX bike, and may well be more reinforced. They will rarely have pegs fitted, and will generally run only a rear u-brake. Also, the tires will be treaded, as opposed to the slicks and semi-slicks used for park riding. Large, padded seats are also popular for a smoother landing if the jump is not done properly and are also easier to hold for in-flight tricks; However some riders do not find seat size an issue. The gear ratio is generally around 44:16, 36:13, 33:12, 30:11 or 25:9 though using small gearings such as 25:9, known as ‘micro gearing’, has become popular.