What is the difference between MTB bicycle frames and the frames of the rest of the bicycles?

Mountain trail bikes (MTB) have a frame designed for travelling on rough surfaces. The frame tends to be longer and lower than a road bike frame, and has a longer distance between the steering axis and the tire’s contact with the ground. These features make the bike more stable and easier to keep moving in a straight line on rough surfaces. While this is a definite advantage on a mountain trail, it is a disadvantage on a crowded city street where being able to make tight turns is essential.

The other big difference between MTB  frames and road-type bike frames is the position of the rider. Bicycles intended for travelling on roads are built to encourage a forward-leaning position. The forward position allows the rider to generate more power with the legs for commuting long distances. MTB frames are designed to encourage the rider to sit upright over the center of gravity of the bicycle for improved stability over rough terrain.MTB bicycle frames also tend to emphasize “sturdiness” and road bike frames tend to emphasize “light weight” in their construction, because MTB bikers are more likely to bounce over rocks and crash into trees than road bikers. Road bikers want to be able to achieve high speeds with as little pedaling effort as possible.