CarBrandLogos archive · Triumph Motorcycles · 1937

Triumph MotorcyclesSpeed Twin

Edward Turner's 500 twin set the template British bikes followed for thirty years.

Photo: London Motorcycle Museum · CC BY 3.0

The story

A defining chapter in Triumph Motorcycles history.

Explore the ideas, engineering and context that shaped the Triumph Motorcycles Speed Twin, then continue into its specifications and place in the marque's lineage.

Origins

Edward Turner arrived at Triumph in 1936, when Jack Sangster of Ariel bought the ailing Coventry motorcycle business, and within a year he had drawn the machine that would reorganise the whole British industry. Announced for the 1938 season, it used a 498 cc parallel twin with a 360-degree crank — both pistons rising and falling together — and pushrod overhead valves, at a moment when the big single was the default and twins were regarded as heavy, complicated and expensive to build.

Triumph Speed Twin motorcycle · Thruxton · CC BY 3.0

Design and engineering

Turner's achievement was making a twin that behaved like a single on the balance sheet. The engine was narrow enough to sit in the existing Tiger 90 single's frame, and the finished machine weighed barely more than the bike it stood beside in the catalogue. What the customer got in return was smoother running, a broader spread of power, easier starting and an exhaust note the market took to at once. Finished in Amaranth red, it sold as quickly as Triumph could build it.

In production

A tuned version, the Tiger 100, followed within a year. Then the war intervened: Triumph's Priory Street works was flattened in the Coventry raid of November 1940, and the company rebuilt at a new factory at Meriden. Production resumed in 1947 and ran until 1966, by which point the same basic architecture had been enlarged into the 650 cc Thunderbird and Bonneville and had become Triumph's entire reason for existing.

Legacy

The wider consequence was imitation. BSA, Norton, Royal Enfield, AJS and Matchless all put vertical twins into production within a few years, and the format defined British motorcycling until Honda's four-cylinder CB750 arrived in 1969. Triumph revived the name in 2018 for a modern parallel twin, which is the clearest indication of how much weight those two words still carry.

At a glance