The Triumph Speed Twin was a 490cc, 4-stroke, street motorcycle manufactured by Triumph from 1937 through 1958.
The Speed Twin was the basis for all Triumph twins until the 1980s. Its four-speed transmission was a simple design that would be used in several Triumph models over the years.
- 27 brake horsepower and tunable to 50 bhp for racing
- Four-speed transmission in separate case
- Top speed: 92 mph