Street & Dirt
The origins of BMX can be traced back to the US as far back as the early 1970's when kids started adapting street bikes to race on dirt tracks, copying the popular sport of motocross. BMX (bicycle motocross was born). Since those early days BMX has developed into various disciplines including BMX racing, street riding and park riding (freestyle). Many of today's purpose built BMX bikes are manufactured from a form of steel although aluminium is also used on some racing models. The quality and strength of steel (or in some cases chromoly) depends on budget and requirement. A bike that is needed for street riding will need to be strong enough to take the bumps and grinds of everyday riding.
Early BMX bikes tended to have a larger front chainring (44 tooth) with a 16 tooth sprocket at the rear. Today the introduction of the cassette hub has allowed the rear sprocket to be much reduced in size (as small as 8t). This means that the front chainring need not be so large and today BMX bikes commonly have nothing larger than 36 tooth with some bikes having as small as 23 tooth. A larger chainring may be fitted onto bikes for BMX racing to allow for higher ratio pedalling and more speed. The smaller chainring on freestyle bikes gives more clearance for certain stunts and grinds.
BMX racing bikes may have larger wheels sometimes 24in with narrower tyres and are obliged to have a full set of working brakes. Bikes designed for freestyle tend to have 20in wheels with tyre choice dictated by terrain (more tread for loose or gravel type surface). Brakes on such bikes may be removed to allow for more freedom when performing stunts although the fitting of a rotor headset allows the front brakes to function even when the bars are spun. There are BMX models designed for younger and smaller riders and these usually have smaller 16in or 18in wheels but the shape and style of the bike remains very much BMX. So whether you want a bike to race or for park, street and freestyle riding, there's sure to be a suitable BMX bike just for you.