Mountain biking is the sport of riding bicycles off paved roads. It requires endurance, bike handling skills and self-reliance. It is an individual sport performed on dirt roads, fire roads, access roads, park trails and mountain trails. There are aspects of mountain biking that are more similar to trail running than regular bicycling. Because riders are often far from civilization, there is a strong ethic of self-reliance in the sport. Riders must learn to repair their broken bikes or flat tires to avoid being stranded miles from help. This reliance on survival skills accounts for the group dynamics of the sport. Club rides and other forms of group rides are common, especially on longer treks.

It is roughly broken down into three categories: cross country, downhill, and freeriding. However all mountain bikes have a somewhat similar look, knobby tires, large round tubing, and usually some sort of suspension or shock absorbers. Mountain biking can be done anywhere from a back yard to a gravel road, but mountain bikers often prefer to ride trails they call singletrack, a narrow trail that winds through forest or fields. Mountain bikers describe a sense of euphoria that results from singletrack or downhill riding.

History of mountain biking
Bicycles have been ridden off-road since their invention, however the modern sport of mountain biking primarily originated in the United States in the 1970s. There were several groups of riders in different areas of the country who can make valid claims to playing a part in the birth of the sport. Riders in Crested Butte, Colorado and Cupertino, California tinkered with bikes and adapted them to the rigors of off-road riding. Other riders around the country were probably copying their friends with motorcycles and riding their bikes on trails and fire roads. However, a group in Marin County, California is recognized by the Mountain Bike Hall of Fame to have played a central role in the birth of the sport as we know it today. They began racing down Mount Tamalpais (Mt Tam) on old 1930s and '40s Schwinn bicycles retrofitted with better brakes and fat tires. This group included Joe Breeze, Otis Guy, Gary Fisher and Keith Bontrager, among others. It was Joe Breeze who built the first new, purpose-made mountain bike in 1977. Tom Ritchey built the first regularly available mountain bike frame, which was accessorized by Gary Fisher and Charlie Kelly and sold by their company called MountainBikes (later changed to Gary Fisher Bicycle Company). The first two mass produced mountain bikes were sold in 1982: the Specialized Stumpjumper and Univega Alpina Pro.

In 1988 the Mountain bike hall of fame was founded, to chronicle the history of mountain biking, and to recognize the individuals and groups that have contributed significantly to this sport.


Equipment
Mountain bikes differ from road racing bicycles in several ways. They have a smaller and stronger frame, knobby tires on wheels that are wider, a lower range of gears to facilitate climbing up steep hills and over obstacles, a wider flat or upwardly-rising handlebar that allows a more upright riding position, and usually some form of suspension system for either the front wheel or both wheels. The inherent comfort and flexibility of the modern mountain bike has led to an estimated 80% market share in countries like the United States, United Kingdom, Canada, Australia, and New Zealand.

While it is estimated that only between 10 and 20% of mountain bikes are actually ridden off-road, the sport of mountain biking has seen an explosion in popularity and diversification.

For more details on this topic, see Mountain bike. 

Advocacy
Mountain bikers have faced land access issues from the beginnings of the sport. Areas where the first mountain bikers have ridden have faced serious restrictions or elimination of riding.

Many trails were originally fire roads, animal paths, hiking trails, or multi-use paths that were simply used for these new trail users. Single-track mountain biking creates more conflict with hikers, particularly in forested areas. There is also some concern single-track biking leads to erosion. Because of these conflicts, the interpretation of the Wilderness Act was revised in the U.S. Congress to be able to exclude bicycles in certain areas.

Opposition to the sport has led to the development of local, regional, and international mountain bike groups. The different groups that formed generally work to create new trails, maintain existing trails, and help existing trails that may have issues. Groups work with private and public entities from the individual landowner to city parks departments, on up through the state level at the DNR, and into the federal level. Different groups will work individually or together to try and achieve results.

Advocacy organizations work through a variety of means including education, trail work days, and trail patrols. Examples of the education an advocacy group can provide include: Educate local bicycle riders, property managers, and other user groups on the proper development of trails, and on IMBA's rules of the Trail. Examples of trail work days can include: Flagging, cutting, and signing a new trail, or removing downed trees after a storm. A trail patrol is a bike rider who has had some training to help assist other (including non cyclists) trail users.

IMBA, the International Mountain Bicycling Association (IMBA) is a non-profit advocacy group whose mission is to create, enhance and preserve trail opportunities for mountain bikers worldwide. IMBA serves as an umbrella organization for mountain biking advocacy worldwide, and represents more than 700 affiliated mountain biking groups.

In 1988, five California mountain bike clubs linked to form IMBA. The founding clubs were: Concerned Off Road Bicyclists Association, Bicycle Trails Council East Bay, Bicycle Trails Council Marin, Sacramento Rough Riders and Responsible Organized Mountain Pedalers.

Other advocacy groups include:


Regional U.S. advocacy groups
NEMBA - New England Mountain Bike Association 
SORBA - Southeast Off-Road Bicycle Organization 

State advocacy groups
HMBA - Hoosier Mountain Bike Association 
KYMBA - Kentucky Mountain Bike Association 
MMBA - Michigan Mountain Bike Association 
MORC - Minnesota Off Road Cyclists 
OMBA - Ohio Mountain Bike Association 
VMBA - Vermont Mountain Bike Association 
WORBA - Wisconsin Off-Road Bicycling Association 
WOMBATS Women's Mountain Bike And Tea Society 

Regions within a state
NIMBA - Northern Indiana Mountain Bike Association 
CAMBA - Cleveland Area Mountain Bike Association 
NorCAMBA - Northern California Mountain Bicycling Association 
Friends of the Wheel, Burlington area, Chittenden County, Vermont 
WNYMBA - Western New York Mountain Bike Association 
FooMTB - Friends of Otero Mountain Biking 

City/local advocacy groups
Outback Trailblazers - Portage, Indiana 
MOCA - Minneapolis Offroad Cycling Advocates - Minneapolis, Minnesota 

Types of Mountain Biking
Mountain biking can more or less be split into nine different categories:

BMX Or Bicycle Motocross is a bike with 20 inch wheels, and used commonly at a skate parks or on dirtjumps. BMX bikes are easier to do tricks on.

Cross Country is just going out and riding your bike up and down hills. It's the least extreme form of mountain biking, but most XC riders will be very fit, and go on long rides. XC riders generally prefer to keep at least one wheel on the ground.

CycloCross is a cross between road and mountain biking. Riders have to go over obstacles, cross rivers, and race on off-road courses and on road.

Dirt jumping is jumping the bike over large man made dirt jumps and then doing tricks while they are in the air. The jumps are built close together so that the rider will go over about six or so jumps in one run. Also, having a flow to give them more speed to do a bigger jump.

Downhill is generally racing bikes downhill as fast as possible. Obviously it would still be downhill if it were not in competition, but most people would consider that to be leaning more towards freeride. In general, it is the custom to either be shuttled to the top in a vehicle, walk the bike (hike a bike), or carried by a ski lift as opposed to pedaling to the top of the trail.

Freeride is basically anything you want it to be. Some people believe that freeride is more of a marketing term than anything. It can be anything from hucking (jumping) your bike off huge drops, to just going out and messing about on your bike.

Single Speed not to be confused with fixed gear, is form of XC mountain biking that is done using a bike that has only one gear (approx. 2:1 ratio) and generally fewer components. The idea is simplicity. The straight chain line provides efficient pedaling. Fewer components means fewer mechanical problems and a lighter weight bike.

Street/Urban riding consists of riding in urban areas, riding on ledges and other man made obstacles. Riders will do tricks as well as stalls and grinds.

Trials is considered to be part of mountain biking, although the bikes look almost nothing like mountain bikes. They use either 20" or 26" wheels and have very small, low frames. Riders will hop and jump their bikes over obstacles, generally urban. This requires an excellent sense of balance.


The Environmental Impacts of Mountain Biking
Properly built mountain bike trails have little environmental impact. Studies reported in the IMBA (International Mountain Bike Association) Trail Solutions manual show that mountain biking's impact is comparable to or even less than other forms of trail use. Irresponsible use (such as using a trail when it is too wet) can be damaging whether on foot, on a bike, or on horseback. It is clear that other activities such as horseback riding and ATV or motorcycle use are far more damaging. Also, often times improper routing or trail construction techniques result in a trail that does not hold up well to any kind of use. Riding in rainy conditions can put ruts and holes in the trail, making it unusable.