Downhill ( downhill , eng. Downhill - “down the hill”) is an extreme mountain bike racing discipline, the essence of which is the passage of the track for a while. A typical downhill track contains various sections - steep descents, sharp turns (counter-declines), bumps in the form of pits and bumps, protruding stones and tree roots, sometimes more complex obstacles are constructed in the form of jumps and cliffs . The average speed of athletes on the track is about 36 km / h, the average height difference is 500 meters per 1.5-2 km.
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Content
Bicycles and gear
Modern downhill bikes weigh between 13 and 18 kg. They have a cushioning system for both wheels, as well as a special frame geometry that is different from ordinary mountain bikes: obstructed fork and seat post angles to increase stability at high speeds. The rear suspension is most often with a stroke of 180-200 mm. Modern forks have a two-crown design and a stroke of 8 "or 203 mm. They use very powerful (usually 4-piston) brakes and are equipped with large brake discs (rotors) with a diameter of 180-220 mm.
A modern bike for downhill racing is equipped with wheels with a diameter of 27.5 "(standard 650B), which replaced the previously prevailing 26" wheels. In 2017, at the first stage of the World Cup in downhill in Lourdes [1] (French Lourdes), for the first time, bicycles with wheels with a diameter of 29 "with forks of the specialized FOX 49 series were widely used, and already in 2018 large-scale bicycle manufacturers presented serial bicycles for 29 "wheels that will be available to all comers. [2] [3]
Also, in order to withstand blows to stones and serious loads after springboards, special reinforced rims are used in downhill. As with bicycle frames, they are made of aluminum or carbon fiber.
The wheels are equipped with wide tires (up to 3.0 ") - for maximum grip on the terrain, have an aggressive tread pattern. Tubeless wheels with special foam inserts are widely used to protect the tire and rim from damage when hitting sharp stones. [4]
A wide wheel (760-820mm) and a short take-out wheel (40mm) are placed on DH bikes for maximum control of the bike. [five]
In downhill skiing, body protection, a helmet with face protection (full face), neck protection, as well as additional protective devices for individual parts of the body (knee, lower leg, elbow, ankle, hand, thigh, etc.) are used to protect against serious injuries in case of unexpected falls. Special masks are put on that completely cover the remaining surface of the face and protect the eyes from dust, midges, wind, dirt and other things. Special gloves with hard inserts are used that completely cover the cyclist’s brush to protect the bones of the brush when dropped.
Also use protection for the torso (the so-called tortoise). Protects all important parts of the body (chest, shoulders, back, stomach) and elbows when dropped.
See also
- Freeride (bike)
- Speed climb
Notes
- ↑ UCI MTB World Cup 2017, France: DH1 . Red Bull Date of appeal September 10, 2018.
- ↑ M29 FRO // Only 15 Available Globally . Intense Cycles Inc. Date of appeal September 10, 2018.
- ↑ COMMENCAL SUPREME DH 29 . www.commencal-store.co.uk. Date of appeal September 10, 2018.
- ↑ MagicStripe - the Russian analogue of the Hucknorris anti-breakdown tape / Personal blog (rus.) , Twentysix . Date of appeal September 10, 2018.
- ↑ Downhill - extreme bike descent