Mountain bikes are incredibly versatile, much more so than road bikes. You give up speed and efficiently on pavement and you get back a bike that can go almost anywhere. But even mountain bike manufacturers divide their products into separate categories. You will often see categories like “trail”, “cross-country”, “all-mountain”, “enduro”, “downhill”, and “fat” bikes.
Downhill or Park style: This type of riding is done primarily at lift-serviced bike parks during the summer at your local ski area. Downhill bikes are full-suspension and are heavy, with maximum suspension in the front (200 mm+) and rear of your not-good-for-riding-uphill bike. I refer to them as motocross bikes without the motor. Tires are big and very knobby. Riders will wear full body armor and face-shield helmets.
This style of riding is not for the faint of heart. It can be brutal with lots of injuries. Two years ago I dislocated my arm, broke elbow bones and tore all the soft tissue and my doctor told me that he see’s my same injury 10 times per week coming in from the local mountain bike park. Yikes.
This style is for young people and those who haven’t gotten beaten into old age.
All-mountain / Enduro style: The term enduro comes from the moto racing world and describes a competition where downhill sections are timed and uphill sections are not. This style of riding is aggressive, downhill and technical but in the “backcountry” of single and eroded double-track trails. The bikes are more functional going uphill than downhill-specific bikes but are less versatile than XC or Trail bikes. Generally, they have more travel in the front suspension (around 150 mm) and are beefier than XC or Trail bikes with wider tires.
Trail: Next in line is the style that focuses equally between technical downhill riding and uphill/rolling cross-country terrain. This is the most common mountain biking style and it’s all about variety. The bikes are the most popular mountain bikes, with decreased weight, mid-range front fork travel (120-150 mm) and bike geometry that favors comfort over pure performance. These are mostly full-suspension bikes.
Cross-country (XC): This style of mountain biking is all about climbing and speed for longer, epic rides in the backcountry. The most important variable in XC bikes is low weight and efficient / smooth shifting. The bikes ability to deal with technical terrain sections takes a backseat to rolling efficiency and pedaling. Very light, very expensive full-suspension bikes are used here or commonly used hardtail mountain bikes.
Fat biking: The newest entry in the riding styles arena. These bikes are designed for riding on snow and sand, or anywhere you need ridiculously huge tires (as wide as 5 inches) for maximum grip. This riding style is all about 4-seasons cycling.