Cycling

Cycling, often called bicycling or biking, involves riding a bicycle or other pedal-driven, human-powered vehicles like balance bikes, unicycles, tricycles, and quadricycles. People around the globe cycle for transport, recreation, exercise, and competitive sport. The activity gained widespread popularity in Europe and North America during the late 19th century, especially in its final decade. Today, more than half of all humans can ride a bike.

Bicycles have served in warfare for reconnaissance, troop transport, and moving supplies, largely replacing horses in these roles. During the Second Boer War, both sides used bikes for scouting. In World War I, France, Germany, Australia, and New Zealand moved troops by bicycle. Japan deployed around 50,000 bicycle troops during its 1937 invasion of China, and similar forces played a key role in Japan's advance through Malaya in World War II. Germany also used bicycles in World War II, while British forces employed airborne "Cycle-commandos" with folding bikes. In the Vietnam War, communist forces relied heavily on bicycles as cargo carriers along the Ho Chi Minh Trail. Switzerland was the last country to maintain a bicycle-troop regiment, disbanding its final unit in 2003.

The most common road vehicle in many countries is the utility bicycle, which features a relaxed frame geometry that cushions the rider from road shocks and makes low-speed steering easier. These bikes often come with mudguards, pannier racks, and lights for daily use. Because bicycles are so effective for transport, companies have created ways to carry everything from groceries to children. Some countries, like Denmark and the Netherlands, have the highest number of bicycles per capita and rely on them as a primary mode of transport. Road bikes, by contrast, have a more upright shape and shorter wheelbase, making them more maneuverable but harder to ride slowly. Their low or dropped handlebars force the rider to lean forward, engaging stronger muscles like the gluteus maximus and reducing wind resistance at high speeds. Designed for speed and efficiency on paved roads, road bikes feature lightweight frames, skinny tires, drop handlebars, and narrow saddles, making them ideal for racing, long-distance riding, and fitness. Other common types include gravel bikes for mixed surfaces, mountain bikes for rugged terrain, and e-bikes with motorized assistance. Many variations exist.

New bicycle prices range from about US$50 to over US$20,000, with the most expensive being a custom Madone by Damien Hirst sold for US$500,000. Quality, type, and weight affect cost; the lightest road bikes can weigh as little as 3.2 kg (7 lb), though UCI regulations set a minimum race-bike weight of 6.8 kg (14.99 lbs). Prospective buyers should get measured and take a test ride. Drivetrain components also matter: a middle-grade derailleur suits beginners, while many utility bikes use hub gears. For significant hill climbing, a triple-chainring crankset may be preferable; otherwise, a lighter, simpler double chainring is common, even on high-end race bikes. Fixed-wheel bikes are also available. Many road and mountain bikes use clipless pedals that attach to special shoes via cleats, letting riders both push and pull on the pedals. Other accessories include lights, bells or horns, child seats, cycling computers with GPS, locks, bar tape, fenders, racks, panniers, water bottles, and cages. For basic maintenance, cyclists can carry a pump or CO₂ cartridge, puncture repair kit, spare inner tube, tire levers, and Allen keys. Special shoes, gloves, and shorts improve comfort and efficiency; waterproof gear like capes, jackets, trousers, and overshoes helps in wet weather, and high-visibility clothing reduces risk from motor vehicles. Some jurisdictions legally require helmets, lights, reflectors, and audible signaling devices like bells or horns. Optional extras include studded tires and a bicycle computer. Bikes can be heavily customized with different seats, handlebars, and gearing to suit the rider's strength and terrain.

Whether to cycle or use other transport depends on many factors for each trip: cycling infrastructure (surface, road space, parking), perceived traffic safety, weather and climate, personal fitness, motivation, route length and steepness, and the performance of available vehicles. Under favorable conditions—a medium-distance trip on a flat or slightly downhill surface in pleasant weather—most healthy people find cycling a practical choice.