A bicycle, or bike, is a human-powered vehicle with two wheels. It has a frame, a seat, pedals, and a metal chain that connects the pedals to the rear wheel. A cyclist, or bicyclist, sits on the seat and pushes down on the pedals with their feet to move the bicycle forward.

The bicycle was invented in 1817 by German professor Karl von Drais, although it wasn’t practical for use until around the 1860s. The early bicycles were unstable, and riders could easily fall off. The modern bike has been made much more stable by adding a crank on the front and back of the bicycle, and chaining the cranks to the wheels. Today’s bikes also feature a range of gears that allow the cyclist to increase or decrease their speed as they ride.

Some bike components are specialized for particular kinds of riding, such as suspension seat posts and suspension wheels. Bicycles are often made of aluminum alloy, and carbon fiber frames and wheels are increasingly common in higher-end models. The bicycle has been called a “mechanical work of art” for its elegant design, and many innovations have been made to make it more efficient and comfortable.

During the Industrial Revolution, bicycles helped reduce overcrowding in urban areas by allowing people to commute into town from suburban dwellings, and they were the most effective means of transport for long distances when compared with walking or horse-drawn carts. The modern bicycle is incredibly efficient, in biological and mechanical terms: Up to 99% of the energy that the rider puts into the pedals is transmitted to the wheels, allowing a person to travel up to three times as far as walking for the same amount of energy.

The most common kind of bicycle is a road bike, which is designed for riding on paved roads. The earliest bikes were heavy and difficult to balance, but improvements in materials and engineering allowed for lighter, more maneuverable designs. Road bikes have since evolved to offer a wide range of features, from lightweight racing frames to full-suspension mountain bikes.

Bike reviews can be useful in determining which type of bicycle to buy, but they should be read with caution. Some reviewers use their reviews as an opportunity to puff themselves up, telling the world how great they are and how fast/smooth/fly/rad they think their bike is. This sort of review is more about showing off than helping the reader, and it can annoy other readers who are looking for useful information.

Some of the best bike reviews are written by people who actually ride the bikes they’re reviewing. Reading reviews from people who know the sort of riding you’re interested in can help you understand what different bikes can do and which ones might be good choices for you. Reviews from people who don’t know the biking scene you’re in can be more confusing, and they may focus too much on the technical details of a bicycle that aren’t important to you.