What are mountain biking categories?

If you have a competitive streak a mile wide and an affinity for putting your bike through its paces, you may want to give these mountain bike racing a try. With several different styles, you're sure to find one you like. Don't forget a helmet.

Cross country. Cross-country (XC) mountain biking is an endurance sport, and one of the oldest and most popular forms of mountain biking. With most events ranging from just a few miles to more than 100 miles (160 kilometers), multiple lap and sometimes multiday races can test the strength and endurance of any hardened rider. Most competitive mountain biking courses involve long stretches up and down hills, so riders need to be fit and efficient cyclers with bikes that can handle both uphill and downhill riding. Cross-country bikes are generally the lightest of all the mountain bikes, weighing in between 21 and 28 pounds (9 and 12 kilograms) [source: Partland].

Downhill. Downhill mountain biking isn't as simple as it sounds. While it may be easy to coast down a long, paved hill, a downhill mountain biking run can be steep and full of obstacles. Rocks, ditches and other unknown debris are everywhere, and since your downhill speed is increased by gravity, you have to think fast to avoid mishaps, like tumbling over the handlebars. Downhill mountain bikes are built tough to take a beating, with great suspension to ease the rocky ride. As a result, they tend to be heavier than other mountain bikes -- more than 35 pounds (15 kilograms) -- which makes them less than ideal for cross-country or uphill riding [source: Snyder].

Four cross (4X). In this type of mountain bike racing, four cyclists are pitted against each other in a race through a series of natural and man-made obstacles. The course can be very technically challenging, featuring a host of bumps, hills, jumps, sharp turns and steep drop-offs. It's usually only a few hundred yards long.

Dual slalom. Have you seen those Olympic skiing events where skiers dodge in and out of a series of colored poles at breakneck speed? Replace the snow and the skis with dirt and a mountain bike, and you have the gist of dual slalom racing. In dual slalom, two bikers race to the bottom of a hill while strategically zigzagging in and out of gates (poles with flags on them).

Up to this point, we've discussed a number of mountain bike racing categories. Not all mountain biking involves trying to get the fastest time. On the next page, we'll explore some of the more leisurely but still potentially death-defying categories of mountain biking.

Mountain biking doesn't always involve flying along with the clock breathing down your back. Still, the following types of mountain biking are anything but boring.

Trials. While most biking competitions are about speed, trials are the exception. Trials are about agility, balance and a little bit of creativity. Whether hopping across a narrow beam on the bike's back wheel or navigating up and over a log or rock, the goal is to complete the course with as few mistakes as possible. What constitutes a mistake? Depending on the trial, it can be letting your feet or certain parts of the bike touch the ground, or missing an obstacle. Because trials focus more on maneuvering and less on riding, these mountain bikes are possibly the strangest looking ones out there -- they usually have small wheels, strong brakes and no seat.

Urban/Street. This category is more commonly known as urban, freestyle or street BMX (bicycle motocross). These are the riders you see sliding down handrails on their pegs, jumping over benches and banking their wheels off walls in the middle of cities, on playgrounds and just about anywhere else that could be used for stunts. Riders in this category focus on tricks, agility and making good use of whatever is around them to get some air. Freestyle BMX bikes often have small wheels, wide tires and pegs (metal bars sticking out from the middle of the wheel) that can be used for sliding down things or for the rider to stand on when performing a trick.

Dirt jumping. Dirt jumping resembles urban BMX in that it incorporates jumps and tricks, but it's different in that the tricks are performed on dirt hills and mounds. Dirt jumpers usually spend a lot of time digging and building their own dirt jumping courses. Since dirt jumping bikes can take a beating, they're built strong and tend to be heavier than other bikes -- usually more than 30 pounds (13 kilograms).

All-mountain. The all-mountain category refers to your basic mountain biking. All-mountain involves riding long trails with lots of ups and downs. It is sometimes called enduro, which reflects the long-distance, endurance aspect of this type of riding. All-mountain bikes are pretty popular in the bicycle market. They have a lot of gears to handle both uphill and downhill riding, are built light enough for uphill riding and are tough enough to take hits.

Freeride. This mountain biking niche occupies the middle ground. This category is the go-anywhere, do-anything type, with an all-around bike to match. Whether you build it or find it, if you can put a wheel on it or jump it, it's freeriding. It's all about getting out and cycling. Freeride bikes have a lot of all-around features like all-mountain bikes, but they tend to be heavier and therefore not as good for riding up hills.

For more about mountain biking, racing and bicycling in general, ride over to the next page.