The bicycle is a two-wheeled vehicle that’s propelled by pedals and steered with handlebars. It’s the most efficient human-powered machine in terms of how much energy a rider expends to travel a given distance, and it’s also the lightest means of carrying a load.

The basic form of the modern bicycle has changed very little since the first chain-driven model was developed around 1885. But advances in materials and computer-aided design have enabled a wide range of specialized designs.

Most bikes have brakes that work by applying friction between the metal brake shoes and the inner rims of the front and rear wheels. When you use the brake levers, the shoes clamp onto the wheel rims and convert your kinetic energy into heat, which slows the wheels and stops the bike. Most bikes also have a front and rear derailleur, which shifts the chain from one chainring to the next so you can select the gear that’s best for your current situation.

In order to ride safely, you need to be aware of the hazards that are on and around your bike, such as potholes, cracks, puddles, gravel, storm grates, railroad tracks, dogs, and other riders. It’s also important to be on the lookout for things that might cause you to lose control of your bike, such as parked cars opening doors or pulling out from behind you.

If you’re riding in a group, be sure to stay close to the leader so that you can hear and see warnings about things ahead. You should also be ready to shift gears and adjust the brakes if necessary, and you should always keep both hands on the handlebars. If you’re riding on a busy road, wear a helmet. It may be uncomfortable, but it’s essential to avoid head injuries in the event of a crash.

If you’re planning to write an article for Cycle, make sure it has something that other Cycling UK members will want to read about. A long, involved or just plain boring opening paragraph can deter readers from continuing to read your article. So keep your articles concise and interesting.