A mountain bike is a rugged, performance bicycle used for two different types of racing, downhill and cross-country.
The name seems a bit misleading. "Off road bike" might be more accurate, but the name came about because the bicycle was originally designed for riding down mountain trails and cross-country racing came later. (In fact, the bikes used for the two types of racing are now considerably different from one another.)
As a downhill sport, mountain biking seems to have originated with the Morrow Dirt Club, a loose organization of 10 cyclists who began riding their bikes down fire trails in Cupertino, California, in 1974.
At the time, the bicycle typically used for off-road racing was a so-called "klunker," a one-speed bike with fat, balloon tires. But the Morrow Dirt Club riders, led by Russ Mahon, had put together bikes with fat tires, thumbshift-operated 10-speed derailleurs, and drum brakes on the front and rear wheels.
Mahon and some of the other Morrow cyclists entered the West Coast Cyclocross Championships in Mill Valley, California, on December 1, 1974. Their unusual bikes caught the attention of three riders from Marin County, Joe Breeze, Gary Fisher, and Charlie Kelly.
Those three, along with Tom Ritchey, went on to create mountain biking. They began by piecing together off-road bikes similar to those they'd seen at the cyclocross race. Then they tried them out on dirt trails and on the Cascade Fire Trail near Fairfax, California.
Other cyclists had gone down the trail during the previous four or five years. They called it "Repack Road," because the ride vaporized the grease on their hub coaster brakes, which then had to be repacked with new grease.
On October 21, 1976, the first formal Repack Road race was run down the twisting, 2.1-mile trail, which drops about 1,300 feet. Charlie Kelly and Fred Wolf were the organizers. The ten riders who entered started at two-minute intervals. Alan Bonds, the only one who didn't crash, was the winner.
The race became a weekly event for nine weeks, with more and more riders showing up each time it was held. Just as important as the race itself was the fact that cyclists were gathering regularly to discuss their ideas about what kind of bike was the best for that kind of terrain.
By 1977, there was so much interest in the sport that Joe Breeze formed a company to produce Enduro mountain bikes. A year later, Kelly and Steve Ritchey founded a company called MountainBikes.
The sport spread rapidly, but cross-country riding and racing soon became its major emphasis, although there were still races down mountain trails. The National Off-Road Bicycle Association (NORBA) was founded in 1983 to govern both types of mountain biking, and the International Mountain Bicycling Association held the first world championships in 1990.
NORBA is now a division of USA Cycling and the International Cycling Union has taken over as the worldwide governing body. Mountain biking became an Olympic sport in 1996, as a cross-country event for men and women.
Two newer types of mountain competition are 4-cross and trials. Both events were added to the world championship program in 2002. The 4-cross replaced the dual slalom event.
In 4-cross competition, four cyclists race down a short course, typically 250 meters, that includes sharp turns and jumps.
In trials, the object is to negotiate difficult sections without any part of the body touching the ground. A course typically consists of five sections, each with a time limit of 2 or 3 minutes. A penalty point is incurred each time part of the body touches the ground and the rider with the fewest penalty points wins.
Mountain bikes used for downhill riding are usually full-suspension bicycles, with front and rear shock absorbers and disc brakes. The cross-country bikes are lighter in weight and they usually have a front shock absorber, but none in the rear, although full-suspension bikes that are light enough for cross-country riding have recently been developed. Another recent development is a hybrid bike on which shock absorbers can be individually locked out.