A bicycle, also called a bike, push-bike or cycle, is a single-track vehicle that uses pedal power to move the rider. It can be ridden by a single person or by two people, known as a tandem, and is designed to be lightweight and simple to operate.

Bicycles come in many shapes, sizes and types. Some are made for children or teenagers; some are geared for adults; and others are built specifically for particular purposes.

Road bikes are designed to be ridden fast on smooth pavement, and can be used for racing or as a form of recreational cycling. They have smooth, skinny tires and “drop” handlebars. These bikes are generally lighter than other types of bicycles, but they’re not comfortable or stable on unpaved trails.

Mountain: Lighter and geared for steep climbs, mountain bikes are ideal for longer excursions. They often have an upright rider position, multi-gear drivetrains and high-end versions may feature vibration-absorbing technology in the frame and/or fork.

Gravel: These models have small wheels and a low center of gravity, making them stable on descents; they’re less efficient than a road bike but are great for kids who like to explore unpaved terrain. They typically have gearing adapted for young riders, and you’ll find rim or disc brakes on them for safer stopping.

BMX: BMX racing models excel at catching air on heavily groomed jumps in bike park trails and skate parks, where trail-builders create takeoff and landing zones that look like swimming pool-like bowls or street features such as boxes and rails. They’re typically built for head-to-head competitions, but some specialty models have specialized components, including special frames, and can be ridden by non-racers as well.

Triathlon: Designed for aerodynamic efficiency, triathlon bikes are designed to help professional and amateur athletes complete their best races. They feature frame geometry that lets the rider maintain an aerodynamic tuck and stable handling, and they’re designed with wing-style airfoil shapes for reducing drag.

Touring: Lightweight and designed for carrying loads, touring bikes have long wheelbases and stable steering. They’re often equipped with accessories, such as racks and bags, to help you pack up for longer rides.

E-bikes: Electric assist bikes with a motor that helps the rider pedal, are popular choices for commuters and people who don’t want to pedal as much. They’re available in three classes: Class 1 provides pedal-assist to 20 mph; Class 2 offers pedal-assist to 28 mph; and Class 3 is a full-on motor that can provide power at speeds of up to 50 mph.

Recumbent: Often considered the most therapeutic option, a recumbent bike is a seated version of an upright bicycle, with the rider sitting in a reclining, rather than an upright, position. They can be uncomfortable for some riders, but they can offer a much more enjoyable and relaxing way to cycle, especially for older or infirm cyclists.

While bicycles have been around for centuries, they really took off in popularity after World War II. During the 1950s, bicycles were introduced to the American market as lightweight, geared bikes that were easy to pedal. They were popular with kids, and during the 1970s the popularity of 10-speed bicycles helped them reach a second peak as young consumers became more adventurous.