There are many different types of bikes that are used for different types of riding and the feeling that the rider likes. There are six main types of mountain bikes which are: Cross country-Used for climbing and low grade downhills, it is and endurance and fitness sport rather than technical skill. Trail bikes-Good for everything and anything to do with mountain biking. Enduro-Can climb but focussed more on downhill trails but still very able to do uphill. Downhill-A bike built for going downhill and nothing else. fatbikes-A bike with fat tyres and minamile suspension built for rolling fast and having fun on. Dirtjumper-For hitting steep dirt and wood kicker jumps.
Bikes