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Motorcycle Grasstrack is a form of motorcycle racing which typically, in its current form, takes place on a flat track consisting of two straights and two bends usually constructed in a field. Undulating hillside tracks were also common in the UK, presenting technically demanding circuits. It is one of the oldest types of motorcycle sports in the UK with the first meetings having taken place in the 1920s. Postwar grasstrack circuits included "permanent" venues such as Brands Hatch and Mallory Park which were not simple oval shapes, although solo motorcycle races were run in an anti-clockwise direction. Later, these were converted into tarmac circuits with races using the more common clockwise direction associated with modern roadracing. Competitors of the postwar era included now-famous names such as Bernie Ecclestone and Murray Walker. In the modern era, it is generally similar to Speedway with races usually taking place over 4 laps from a standing start. Unlike Speedway, which has 4 riders per race, Grasstrack racing can have many riders in each heat and the circuit is normally longer allowing higher speeds. Grasstrack has three solo classes, 250 cc, 350 cc and 500 cc together with three sidecar classes; left-handed 500 cc and 1000 cc (turning left) and right-handed 1000 cc (turning right). Many famous Speedway riders such as 1976 world champion Peter Collins started their racing careers in Grasstrack. Some Speedway riders continue to take part in national Grasstrack meetings when their schedule permits. The British Grasstrack season usually starts in early spring around the Easter holidays and runs through the summer/autumn months. More spectacular racing takes place at larger roped tracks including the Poacher and ASTRA Champion of Champions and Grand Slam meetings in Kent and in particular the most exciting meeting of all at the famous Rhodes Minnis circuit. The pinnacle of the domestic Grasstrack season is the British Masters Championships. This official ACU championship is where the British champion is crowned in the mainstream 500 cc solo and 1000 cc right hand sidecar classes. In Europe the same sport is often called Long Track racing. This is exactly the same setup as British grasstrack which has tracks normally around 600–800 meters in length, but is held on the continent with tracks up to 1000–1200 meters in length and with speeds reaching 90 mph – 100 mph. The machinery used is the same as are the riders. == Grasstrack Motorcycles == Grasstrack racing motorcycles look quite similar to Speedway machines but there are different engine capacity limits for each class. In the UK there are classes for 250 cc (normally 2 stroke engines), 350 cc and 500 cc bikes (usually 4-stroke engines). Unlike Speedway bikes which have no gears, Grasstrack bikes usually have a 2 speed gearbox. Both Speedway and Grasstrack bike have no brakes. The only other main difference is that speedway bikes have no rear suspension and are shorter in length, usually by around 10–12 inches. Also there is a class called Pre-75. These are bikes that have been made before 1975. The three classes in Pre-75, are 250, 350 and 500 cc. As well as solo racing, sidecar racing is also quite popular and often very spectacular. There are mainly three recognised classes, 500 cc (using solo 4-stoke engines) and two 1000 cc classes (using stock road bike engines). Again, they all run on methanol, and the 500 cc class and the 1000cc Lefthand sidecar class run anti-clockwise around the oval track, and the 1000 cc class clockwise. The reason behind the difference in direction is often asked, the main reason being the origin of each class. The 500cc sidecars having been developed in mainland Europe, where drivers drive on the right of the road. The 1000cc sidecar has been developed in the UK where road users drive on the left. Therefore, the sidecar wheel is always found on the nearside of the vehicle. The fastest recorded oval lap record is held by UK's Kelvin Tatum MBE at Rastede (1000 m Grass/Sand surface) in Germany at an average speed of 144.31 km/h. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「grasstrack」の詳細全文を読む スポンサード リンク
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