Presentation on theme: "Mountain Biking Матвеева Ю. и Петрачкова В., 9»А»."— Presentation transcript:
Mountain Biking Матвеева Ю. и Петрачкова В., 9»А».
Downhill bikes and equipment Modern race downhill bikes weigh between 16 to 19 kg (35 to 42 pounds), and usually feature full- suspension and frame geometries that lean back farther (slacker geometry) than other mountain bikes. As of 2006, 203 mm (8-inch) is the 'norm' for suspension travel however some commercially available big mountain freeride bikes can have over 300 mm (12-inch). Large-diameter 203–5 mm (8- inch) hydraulic disc brakes moderate speed. Downhill bikes and freeride bikes are very similar but there are some slight differences. Downhill race bikes typically are much lower and have slacker head angles than freeride bikes, so that the bike is more stable at speed and in corners. Freeride bikes have a steeper geometry and a higher bottom bracket height, so that they are better for balance and maneuverability, however freeride bikes sometimes use single crown forks, which are shorter in travel length and lighter than the dual crown forks often used by downhill riders, dual crown forks usually have around 200 mm (8-inch) of travel, and single crown forks are usually around 180 mm (7 in) maximum. Downhill gear features body armor and full-face motocross-type helmets. Other protective gear such as a neck brace can be added to reduce the risk (by bringing the head to a controlled stop) of neck and spinal injury.
Governing bodies The Union Cycliste Internationale is governing body for downhill mountain bike racing. Racers qualify to compete in World Cup races by earning UCI points, which are gained by being a top ten finisher in certain races, usually national. In the U.S., NORBA, as part of USA Cycling, runs the National Mountain Bike Series, and the NCCA is the governing body for collegiate cycling. In the UK, British Cycling controls mountain biking as well as road and BMX. In Australia, MTBA controls all disciplines of Mountain biking.
Downhill racing venues United States The Sea Otter Classic, held each April at Laguna Seca near Monterey, California, is a major riding event that opens the racing season (course map). The 2006 U.S. National Championships were held at the Infineon Raceway in Sonoma, California. In 2007 and 2008 the U.S. National Championships were held in Mt. Snow, Vermont. In 2009 and 2010 the U.S. National Championships were held at (Sol Vista Bike Park in Colorado.) Plattekill Mountain in the Catskills, Mammoth Mountain, the Northstar at Tahoe, Brian Head Resort, Attitash and Deer Valley ski resorts, and Moab UT are also well known to mountain bikers. In the southeastern United States, Snowshoe Mountain is well known for its extensive mountain bike park, camps, and even freeriding areas during the summer. Vail, Colorado was the site of the 1994 Downhill World Championship. The trail was renamed "'94 Downhill," and is still ridden by many downhill bikers today. It was considered one of Vail Mountain's hardest venues. Aaron Gwin is currently the U.S's top ranked racer on the World Cup Circuit. In 2010 he finished his World Cup Campaign with a 4th place world ranking and a 4th place at the UCI mountain bike world championships. He races for the Yeti/Fox Racing Shox World Cup Team along with teammate Jared Graves.
History The 1st downhill time-trial race took place in Fairfax, California on October 22, 1976 on a fireroad now referred to as Repack Road, due to the need to repack the single rear hub brake after a descent. The bikes used were based on beach cruisers that had a single rear brake that worked by pedalling backwards. A mechanism came into operation causing a conical metal (bronze?) brake shoe to be wound on a thread into a conical metal hub. To prevent a metal to metal brake from snatching it was always filled with grease. Heavy use of the brake during the descent would cause the brake to over heat, melting the grease till it drained from the hub and required repacking. Ten riders descended 1300 feet of Repack in about 5 minutes. The first bikes used for descending were known as "klunkers" or "paperboy bikes": coaster brake cruisers using balloon tires first imported to America by Ignatz Schwinn. By 1979, two organizers and competitors of the Repack downhill, Charlie Kelly and Gary Fisher founded the company which named the sport, MountainBikes. As mountain biking grew enormously during the 80s, downhill riders continued to use either rigid or limited suspension travel (under 2 inches) bicycles, and purpose made downhill bikes were not made until the 90s. Some of these innovations included dual crown suspension forks and disc brakes, as well as very elaborate frame suspension designs.