A bicycle is a two-wheeled vehicle that uses human power to move. The pedals connect to a chain, which then turns the back wheel. This pushes the rider forward, while the front wheel swivels to steer. The bicycle is the most efficient means of human-powered transportation, requiring only about 1% of the rider’s body weight to travel a given distance. It is also the safest way to travel short distances. It is used in many countries as the primary form of transport, and it is an important recreational activity. It is also a common mode of exercise and fitness training.

The bicycle was first developed in the 1860s and has since evolved into a multitude of forms. Early inventors used wood, metal, and leather to build frames for their bicycles. They also experimented with different designs for gears that would enable the cyclist to both pedal and steer the bicycle. They soon discovered that it was necessary to have a separate front wheel for steering and to use a crank, or shaft drive, to efficiently transfer the energy from the pedals into forward motion. The basic components of a modern bicycle include the frame, saddle, handlebars, wheels, and brakes. Many people add accessories to their bicycles, such as a basket or rack for carrying cargo or an auxiliary saddle for a child passenger. Other riders may opt to add a hitch on the rear frame for pulling a trailer.

Some bicycles are designed specifically for racing or speed. These are known as racers’ bikes. They have drop handlebars that allow the rider to hold their hands in a more aerodynamic position. They also have narrower handlebars and a more stretched out geometry that allows the rider to sit further forward and reduce their overall drag. Combined with an efficient drivetrain, these features help racers achieve their fastest speeds.

Bicycles are commonly used for transportation in urban environments. City, or commuter, bikes have flat handlebars and a more upright geometry that is more comfortable for daily riding in traffic and while wearing business attire. These bikes are also built with durability in mind as they can be subjected to more wear and tear than other types of bicycles. Some of these models feature frames with mudguard and rack mounts that make them even more versatile. Some also utilize belt drives that require less maintenance and have a longer lifespan than traditional chains.

Drivers should always be on the lookout for bicycles and give them the same amount of space as they would a car or truck. It is important to keep in mind that, although bicycles can be quite fast, they do not have the same level of control as automobiles. It is also important to wear the appropriate clothing and safety equipment for riding a bike, including a helmet, brightly colored clothing (during the day), and reflective gear (at night or in poor weather). Lastly, cyclists should always ride their bikes within the legal speed limit and obey all traffic laws.