A bicycle is a two-wheeled steerable vehicle that can be powered by pedaling. It is the most efficient means of human propulsion ever devised, allowing riders to travel three to five times as fast as walking while requiring only about half the energy.

There are many different types of bicycles, designed for a variety of riding purposes and terrain. Some of the most common include road bikes, mountain bikes, BMX, tandems, cruisers, and racing bikes. Each has a slightly different frame design, geometry, and componentry that allows it to excel in its particular type of riding.

In general, most bikes are constructed from steel or aluminum alloys. More expensive bikes may utilize carbon fiber, which is both lighter and more resilient than steel. The frame is the core of a bicycle, and it determines its shape and strength. It also defines how the various components of a bike fit together and interact.

Some bikes are built for specific types of riding, such as road, mountain, or track. Some bikes are equipped with suspension, which can make a ride more comfortable over rough terrain. Some bikes are built for racing, in which case they will have a more lightweight and aerodynamic frame.

Bicycles can be adapted to carry luggage and gear, or to tow a child in a trailer. There are also a wide range of accessories available, including cyclocomputers to track speed and distance, padded bike clothes and gloves, and reflectors and racks.

The bicycle originated in Europe at the end of the 19th century, and is the most popular mode of transportation in the world. There are now more than 1 billion bicycles in use worldwide. They are used for recreation, transport, utility work, and sport. People enjoy biking because it is a low-impact, low-cost activity that provides excellent cardiovascular and muscular fitness. It is an ideal form of transport for city dwellers, as it reduces traffic congestion and air pollution. It is also an important form of exercise for the disabled and the elderly, and it can be used as a tool for rehabilitation and physical therapy.

A road trip is any vacation or excursion in a car that involves driving over long distances, usually on highways and freeways. A road trip can be as simple or elaborate as you want, but it’s typically a great way to see a lot of scenery in a short amount of time. Road trips can be made even more fun by listening to loud music and eating lots of snacks.

A bicycle is a two-wheeled machine that can be powered by the user’s feet, and is capable of moving at about 16-24 km (10-15 miles) per hour. It has a frame with a front wheel held in a rotatable fork, and a rear wheel connected to the cranks through a chainwheel. The rider sits on a saddle, and steers by leaning and turning the handlebars. The pedals are attached to the cranks, which are in turn connected to a chainwheel and a sprocket on the rear wheel.