The bicycle is a human-powered, two-wheeled machine for transporting people and things. It is the most efficient means yet devised for converting human energy into motion, and it can carry substantial loads with relatively little effort. It has revolutionized transportation and remains an important form of recreation. Many countries have laws that regulate bicycle use, and most roads are suitable for bicycles. Some countries have separate lanes for them, and others allow cyclists to ride on sidewalks or share paths with pedestrians. In the United States, the Bicycle Act of 1896 created the National Cycle Route System, which consists of a network of bikeways that connect cities and towns.
The most basic bicycle consists of a seat, pedals, and a handlebar connected to a chain and to the rear wheel. The pedals are attached to a crank, which is connected to a chain that drives the back wheel via cogs. The handlebar is connected to the crank and to the front wheel via a steering head, which can be swung from side to side to steer the bike.
Most modern bicycles have a rigid frame made of steel, aluminum, or carbon fiber. The frame is the single most important component of a bicycle in terms of its effect on ride quality and handling, and it sets the stage for how well all of the other parts work together. A wide variety of frames have been designed, from the traditional diamond frame used in racing bikes to the f frame used in many folding bicycles.
Bike technology is constantly evolving. The most recent developments include frame materials and components that are more lightweight, stiffer, and more comfortable than ever before. These advances have allowed cyclists to travel farther and faster with less fatigue. In addition, new materials such as titanium and composites offer greater strength without increasing weight.
Because of their simplicity, most bicycles can be maintained by the owner, a process known as “tinkering”. The most common maintenance items are replacing worn tires, cleaning the chain, and tuning the shifting mechanism. Many bikes are sold with tools specifically for repairing and maintaining bicycles, and the manufacturer’s instructions should be followed closely when performing these tasks. A professional shop can help with repairs and adjustments that are beyond the scope of a casual cyclist’s abilities.
Many bicycles are used for transportation, and the number of people using them has increased as incomes have risen around the world and urban populations have grown. Several cities in the United States have begun to promote the use of bicycles, providing dedicated lanes on main roads, and constructing new bicycle infrastructure, such as paths and bridges for commuters. In addition, there are many organizations that encourage bicycle riding, including bicycle clubs, races, and advocacy groups.
Bicycles can be dangerous, particularly if the rider is not wearing a helmet. Accidents involving bicycles can result in serious injury or death to the rider and other persons, so care should always be taken when riding one.