Downhill bike

From Wikipedia, the free encyclopedia
Jump to: navigation, search
This article is about Downhill bikes themselves. For the associated activity, see Downhill cycling.
A Giant Faith 2 downhill mountain bike with 6.5 inches of travel in the front and 8 inches in the rear.
Racing a downhill bike at Horseshoe Valley In Ontario

A downhill bike (also known as a downhill mountain bike) is a full suspension bicycle designed for downhill cycling on particularly steep, rocky trails. Unlike a typical mountain bike, durability and stability are the most important design features, compared to lighter, more versatile cross-country bikes. Downhill bikes are primarily intended for high speed descent, and downhill riders will usually push, or shuttle via chairlifts or motorized vehicles, to the trailhead.[1]

Downhill bikes are typically made of aluminum, carbon or steel, will have 7–10 inches (178–254 mm) of rear suspension travel, and be designed around a 7–8-inch (178–203 mm) suspension fork.[2] The suspension sag is also much higher than cross-country bikes (25%-50% of total travel vs. 10%-20%) for a more supple ride at higher speeds.

These bikes will also have very slack head tube angles (66 degrees or less),[2] long wheelbases (over 45 inches or 1,143 mm),[2] and will accommodate the use of up to 3-inch (76.2 mm) width knobbed tires. Downhill frames are also overbuilt to handle the stress of riding over rocky terrain, drops, and jumps. Bike weights have been typically over 40 lbs (18 kg), but modern downhill bikes have broken the 45 lb (20 kg) weight barrier (such as the Trek Session 10, weighing in at almost 50 lb or 23 kg). Some newer (2007/8) downhill bikes can be built to weigh under 38 lb (17 kg), such as the Santa Cruz V10 or the GT DHi.

Other features include 8-inch (203 mm) disc brakes and a chain guide to prevent accidental chain deraillment. Other innovations include the use of OnePointFive head tube standard, which uses a 1.5 in (38 mm) wide steerer tube, instead of the more conventional 1.125 in (29 mm) diameter, for added stiffness and strength.[3] Adjustable head tube angles are also available to adapt the bike to the owner's preferred style of riding.[4]

Downhill bikes are also very similar to freeride bikes due to large strong frames and long travel.[1] Most downhill bikes use triple clamp forks which allow longer travel at the front(usually 203 mm or 8 in and increased stiffness that a single crown fork cannot offer. Drawbacks though, are increased weight and reduced turning circle. Also downhill bikes have very thick and big tyres in order not to drift in bad terrain.

See also[edit]

References[edit]

  1. ^ a b Philip Foster (Jul 21, 2011). "What is the difference between a downhill bike and a freeride bike?". LiveStrong. Retrieved 2012-07-13. "The downhill mountain bike is equipped with a heavier frame." 
  2. ^ a b c "Specialized Demo0 Carbon DH mountain bike unveiled - full specs, geometry & more". BikeBoardMedia, Inc. June 2, 2012. Retrieved 2012-07-13. "Running Rockshox Boxxer forks with 8″ and their dual seat stay rear triangle with 8″ of rear wheel travel. Head tube angle = 64º. Wheelbase = 1,171–1,208 millimetres (46.1–47.6 in)." 
  3. ^ "Headset Standards". Park Tool Co. Retrieved 2012-07-13. "The Onepointfive Standard® uses a 1.5-inch diameter (38.1mm) steering column." 
  4. ^ "Cane Creek unveils Angleset: adjustable angle headsets". BikeBoard Media Inc. June 17, 2010. Retrieved 2012-07-13. "Today Cane Creek has officially unveiled their all new Angleset, an adjustable angle headset that lets you fine tune your bike’s handling." 

External links[edit]