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Though originally connoting a bicycle intended for BMX Racing, the term "BMX bike" is now used, generically, to encompass race bikes, as well as those used for the dirt, vert, park, street and flatland disciplines of BMX.
BMX bike frames are made of various types of steel, and (largely in the racing category) aluminum. Cheaper, low end bikes are usually made of steel. Mid range bikes are mostly chromoly or hi tensile steel, which are about the same in weight and strength. High-performance BMX bikes use 4130 chromoly, or generation 3 chromoly.
Sometimes the front axle is 14mm thick, but 3/8" is much more common on modern bikes. The rear axle, however is always 14mm thick, because it has to withstand much more abuse than the front axle does.
The introduction and widespread popularity of the cassette hub has ushered in the use of smaller gearing on bmx bikes. Instead of the old 44/16 gearing found on almost all older bmx bikes, new bikes use gearing such as 36/13, 33/12, 30/11, 28/10, 25/9, and even 23/8. All those gearing ratios feel nearly identical to the old 44/16 gearing when pedaling. Advantages of smaller gearing include lighter weight, and more clearance when grinding. The freewheel hub is all but extinct due to several factors. The smallest freewheels can be made is with 13 teeth, which is larger than most riders prefer. Also, they are less consistent than cassette hub, and skip or jam up far more frequently.
On most freestyle bmx bikes, the front wheel has 36 spokes, but some more abusive riders use 48 spoke front wheels, because they are stronger. The same goes for rear wheels. A lot of bikes use 36 spokes, most commonly on dirt jumping bikes. But 48 spoke rear wheels are very common, especially on street bikes, as they have to withstand harsher and more frequent impacts. Race bike wheels are also usually 36 spokes, but wheels for the smallest racers (sometimes as young as three years old) can be built with 18 or 28 spokes.
BMX Racing bike wheels vary in size, from 18" to 26" (with 20" being the most popular).
Dirt jumping and freestyle bike wheel sizes include 16" and 18" for younger, smaller riders, 20" for most other riders, and a few companies including Haro and Sunday offer 24" freestyle bikes for taller or older riders who feel cramped on a standard 20" bmx bike.
BMX started in the early 1970s when children began racing their bicycles on dirt tracks in southern California, drawing inspiration from the motocross superstars of the time. The size and availability of the Schwinn Sting-Ray made it the natural bike of choice, since they were easily customized for better handling and performance. BMX racing was a phenomenon by the mid-1970s. Children were racing standard road bikes off-road, around purpose-built tracks in [California]. The 1972 motorcycle racing documentary On Any Sunday is generally credited with inspiring the movement nationally in the US; its opening scene shows kids riding their Schwinn Stingrays off-road. By the middle of that decade the sport achieved critical mass, and manufacturers began creating bicycles designed especially for the sport.
George E. Esser founded the National Bicycle League as a non-profit bicycle motocross sanctioning organization in 1974. before they set up the NBL, George and his wife, Mary, promoted motorcycle races with the AMA (American Motocross Association), and through their "National Motorcycle League," or NML. Their two sons, Greg and Bryan, raced motorcycles, but also enjoyed riding and racing BMX with their friends. It was their sons’ interest, and the absence of an Eastern presence by the National Bicycle Association (NBA, at the time the only sanctioning body of BMX Racing), that prompted George to start the NBL in Florida.
By 1977, the American Bicycle Association (ABA) was organized as a national sanctioning body for the growing sport. In April 1981, the International BMX Federation was founded, and their first world championships were held in 1982. Since January 1993 BMX has been integrated into the Union Cycliste Internationale (UCI).
BMX Freestyle (which, today, encompasses the Dirt, Vert, Park, Street and Flatland disciplines) was created by racers who enjoyed pushing the stylistic limits of what they could do on their bikes. Haro Bikes founder Bob Haro is popularly known as "The Father of Freestyle."
BMX Freestyle is now one of the staple events at the annual Summer X Games Extreme Sports competition and the ETNIES backyard jam, held largely on both coasts of the United States. The popularity of the sport has increased due to its relative ease and availability of places to ride and do tricks.
In 2003, the International Olympic Committee made BMX Racing a full-medal Olympic sport for 2008 Summer Olympic Games in Beijing, China. At the games, Latvian Māris Štrombergs and Anne-Caroline Chausson of France were crowned the first Olympic champions in Mens and Womens BMX Racing, respectively.
Many great BMX riders go on to other cycling sports like downhill such as Australian Olympian Jared Graves, former "golden child" Eric Carter, and youth BMX racer Aaron Gwin. Conversely, Mountain Bike racers sometimes cross over to BMX Racing, such as 2008 Olympic Bronze Medalist Jill Kintner of the USA.
Sport and leisure use EditAs a form of leisure activity or sport BMX has become popular. Enthusiastic people, especially children and teenagers will often attend BMX and skate parks and centres and sometimes compete in organised competitions. One form of BMX biking is Freestyle BMX.
BMX bicycles are available several distinct model types