An underbone is a type of motorcycle that uses structural tube framing with an overlay of plastic or non-structural body panels and contrasts with monocoque or unibody designs where pressed steel serves both as the vehicle's structure and bodywork. Outside Asia, the term underbone is commonly misunderstood to refer to any lightweight motorcycle that uses the construction type, known colloquially as step-throughs, mopeds or scooters.
Plastic panels and covers are widely used on modern underbones e.g. Modenas Kriss 2.
MCX Raptor, an underbone from the Philippines.
Honda Winner, an underbone with 150 cc engine displacement.
Plastic panels and covers are widely used on modern underbones, such as a Suzuki FX125
A scooter is a motorcycle with an underbone or step-through frame, a seat, a transmission that shifts without the operator having to operate a clutch lever, a platform for the rider's feet, and with a method of operation that emphasizes comfort and fuel economy. Elements of scooter design were present in some of the earliest motorcycles, and motor scooters have been made since at least 1914. More recently, scooters have evolved to include scooters exceeding 250cc classified as Maxi-scooters.
The Vespa was the first globally popular scooter
TVS Scooty; The term scooty has become the generic term for scooter in India
1919 Autoped Scooter
1894 Hildebrand & Wolfmüller motorcycle
