There are six different types of bicycles: touring bicycle, mounting bicycle, utility bicycle, hybrid bicycle, racing bicycle, the motocross bicycle. Mountain bikes use wide tires for riding on the mountain and have flat handlebars and many different speeds. These mountain bicycles are best for riding on rough trails.
The utility type of bicycle has heavy frames and usually has one speed. These hybrid bicycles are also like mountain bicycles, but the tire of the hybrid bicycle is not as wide as the tire of the mountain bicycle. These hybrid bicycles are best for both roads and off-road trails also.
As Mountain bicycles have wide tires, on the other hand, these racing and touring bicycles have narrow tires in their bicycles and also lightweight frames and handlebars, which are curved and have many different speeds. These bicycles are best for road riding.
That's why it is also known as road bicycles. BMX bicycles are specially designed for racing on dirt tracks. These BMX bicycles have small frames, low seats, and high handlebars at one speed.