Dirt bike

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Dirt bikes

As dirt bikes is stable called mountain bikes with mostly smaller frame (24-26 inches ). They are used for dirt jump . These bicycles are sports equipment and are hardly suitable for normal movement.

They are made of steel or aluminum alloys. Dirt bikes are mainly used for jumping over dirt jumps ( tables and doubles , see also: Dirt Jump ).

Structure and technology

The frame construction, rims , cranks as well as the stem and handlebars must be stable. The frame is usually made of chrome-molybdenum steel or aluminum alloys to provide the necessary stability; the top tube drops sharply towards the rear. Normally, wide tires are used that have a relatively coarse profile but still have as little rolling resistance as possible. The tires are usually around 2.1 to 2.5 inches wide and the wheels are 24 or 26 inches in diameter. Treadless tires ( street tires ) or tires with little tread are also used on particularly flat and dry surfaces , as they are lighter and easier to handle than those with a coarse tread . They can also be used to achieve the desired speed more quickly due to the lower rolling resistance. Many mountain bikes of this type have no gearshift ( single speed ) and usually only have a rear wheel brake with a manual lever on the handlebar. This was deliberately chosen in order to save weight and to be able to turn the handlebars for certain tricks (e.g. barspin ). However, some top riders use one gear shift to get the speed needed when driving the above types of ramps. However, this in turn comes closer to the category 4X or Freeride . Another important component of a dirt bike is the suspension fork : it is available in 2 versions. Either with air or with a steel spring inside. It usually has a spring travel between 80 mm and 140 mm. This reduces the bumps on the bike to a minimum, which is also necessary because some jumps are up to 10 meters or more away and the riders “fly” through the air over several meters. However, there are also some drivers who consciously choose a rigid fork in order to be able to take more speed with them when landing. The pedals that are built into most dirt bikes are called flat pedals or bear paws . To prevent the chain from jumping out, chain guides are used on bikes with derailleur gears. The saddle is usually mounted very low so that it doesn't bump painfully when it bounces after the jump.

Well-known previous and current competitions are the Red Bull Joyride, X-Games and Extreme Playgrounds, the Crankworx series and the Freeride Mountain Bike Tour (FMB Series).

Web links

Commons : Dirt Bike  - Collection of pictures, videos and audio files

Individual evidence

  1. ↑ Michael Gressmann: Bicycle Physics and Biomechanics. Delius Klasing Verlag 2002, ISBN 3-895-9502-38 , p. 213.