Wednesday, April 28, 2010

Freeride and Downhill


A Specialized BigHit II entry levelDownhill/Freeride mountain bike with 180 millimetres (7.1 in) of travel in the front fork and 190 millimetres (7.5 in) in the rear shock.

Freeride (FR) mountain bikes are similar to downhill bikes, but with less emphasis on weight and more on strength. Freeride bikes tend to have ample suspension and typically have at least 6 inches (150 mm) of travel. The components are built from stronger, consequently heavier, materials. They can be ridden uphill, but are inefficient and their moderately slack head tube angles make them difficult to maneuver while angled up a hill or traveling at a low speed. They are effective on technical downhill trails. Frame angles are typically steeper than those found in downhill bikes. This enhances maneuverability over and around small objects. Freeride bikes typically range in weight from 14 to 20 kilograms (31 to 44 lb). The most durable freeride bikes are often too heavy and have too much suspension to be ridden uphill as comfortably as other less-sturdy models, although newer, more expensive bikes come with suspension specifically designed to make them easier to ride uphill.

Downhill (DH) bikes typically have seven or more inches (178 mm) of suspension travel. They are built with frames that are strong, yet light, which often requires the use of more expensive alloys. In the past few years, lighter downhill bikes have been getting below the 40lbs mark (18 kg). Due to their typically large or high gears, long, plush travel and slack geometry angles, Downhill bikes are ideal only for riding down dedicated downhill trails and race courses. Downhill bikes have the most sag of Mountain Bikes to get ample traction to go fast over bumpy trails. Head Angles are often as slack as 64 degrees. Several types of bicycle speed records have been registered downhill.

Due to the high-speed nature of downhill riding most bikes only have one chain ring in the front, a large bash guard and a chain guide, though many racers are now using chain guides without bash guards to reduce weight. Some of the most up to date designs feature internal gearboxes built directly into the frame construction, this modification eliminates the need for the rear derailleur mechanism, although this design has not been widely embraced yet.

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