twowheeled

Twowheeled is an adjective used to describe objects, devices, or vehicles that have exactly two wheels. In transportation contexts, it most often refers to two-wheeled ground transport such as bicycles and motorcycles, but can also include two-wheeled personal transport devices such as electric scooters. The term is distinct from three-wheeled and four-wheeled configurations and is frequently used in engineering and design discussions as a basic category of wheel arrangements.

Two-wheeled vehicles have a long history. Early two-wheel devices appeared in the 18th and 19th centuries as velocipedes and later safety bicycles, which established the basic two-wheel layout with a chain drive and front- or rear-steering. Motorized two-wheelers emerged in the late 19th and early 20th centuries, giving rise to motorcycles, mopeds, and scooters. In contemporary usage, twowheeled distinguishes these from larger or differently configured vehicles used in mass transportation or logistics.

Stability on two wheels relies on a combination of rider input, steering geometry, and dynamic balance. Bicycles use rider movement to control balance, with steering and lean determining trajectory. Motorized two-wheelers rely on gyroscopic effects, traction, and braking systems to maintain stability at speed. Different drive configurations exist: front-wheel drive, rear-wheel drive, or chain-driven rear wheels for bicycles, with electric motors increasingly common in both bicycles and motorcycles.

Two-wheeled vehicles are used for commuting, recreation, sport, and transportation in many regions. They include bicycles, motorcycles, mopeds, and electric scooters. Design choices affect efficiency, weight, handling, safety, and regulatory classification, such as licensing, speed limits, and helmet requirements.