A bicycle is a human powered land vehicle with two wheels and a seat. It is the most efficient means of transport currently available. It can transform up to 90 percent of the energy a rider generates into forward motion. A metal chain transfers the power from a pedal to a crank that drives a rear wheel. A bicycle’s frame gives it strength, while the handlebars and other parts provide control.

A bike is a machine that requires a certain amount of skill to operate, but can be very rewarding. There are many different types of bikes and ways to ride them. Some bikes are suited for racing, while others are designed for touring or transportation. Bicycles can be ridden by men, women, and children of all ages. Bicycling is popular as a recreational activity, and it also serves as an effective form of exercise.

The modern bicycle first emerged as a mode of transport in the nineteenth century. Karl von Drais, a German professor, invented the first steerable two-wheeled device in 1817. His invention was known by various names, including a draisine, Lauf-maschine, hobby horse, and velocipede, but it is the bicycle that most of us think of when we hear the word.

In the 1860s, French inventors developed bicycles with pedals. These new models, which were called velocipedes or ‘running machines,’ became popular in Europe. They were sometimes referred to as boneshakers in the United States because of their rough ride. By the end of the nineteenth century, a variety of innovations had made the bicycle an affordable and practical means of transport for both work and leisure.

There are several different styles of bicycles and a wide range of parts that can be used to make them. The most common type of bicycle has a horizontal frame with the seat located in front of the cranks and a chain connecting the pedals to the rear wheel. There are also vertical frames with the seat situated behind the cranks, and a frame that sits vertically with the seat at the front of the cranks.

Handlebars are available in a number of different configurations, which determine how a cyclist rides a bicycle. Upright handlebars, which were the standard until the 1970s, curve back toward the rider, offering a natural grip and comfortable upright position. Drop handlebars, which were introduced in the 1960s, drop downward and offer a more aerodynamic, crouched position that offers better braking power.

Many large cities employ couriers who deliver mail on bicycles, which are parked in special racks in the city streets. There are also companies, such as DHL Express in Germany, that use cargo bicycles to transport packages. Bicycles are even used by some law enforcement agencies, such as the police departments in San Francisco and Boston. They can maneuver in crowded areas that are difficult for motor vehicles to navigate, and they allow officers to extend the reach of their foot patrols.