Triumph Twenty One (1957 to 1966)

The Twenty One model was introduced in 1957 by Triumph Motorcycles to commemorate the brand's 21st anniversary. It was the first Triumph motorcycle with a unitized engine, integrating the engine and gearbox into a single block. Originally called the Twenty One, from 1959 it was officially designated the 3TA in its 349cc version, while the 498cc version was known as the 5TA. Both featured parallel twin-cylinder engines, 4 speed manual transmissions and chain final drives. A notable feature of these motorcycles was their closed rear fairing, nicknamed the "bathtub," which covered the rear of the bike. A design that made them easily recognizable and, although controversial in the American market, became a distinctive symbol of this era for Triumph. The Triumph Twenty One was produced until 1966.