the United States in 1911. By 1914, motorcycles were no longer just bicycles with engines; they had their own technologies, although many still maintained bicycle elements, like the seats and suspension. The First World War During the First World War, motorbike production was greatly ramped up for the war effort to supply effective communications with front line troops. Messengers on horses were replaced with dispatch riders on motorcycles carrying messages, performing reconnaissance personnel and acting as a military police. American company Harley-Davidson was devoting over 50% of its factory output toward military contract by the end of the war. The British company Triumph Motorcycles sold more than 30,000 of its Triumph Type H model to allied forces during the war. With the rear wheel driven by a belt, the Model H was fitted with a 499 cc air-cooled four-stroke single-cylinder engine. It was also the first Triumph not to be fitted with pedals, so was a true motorcycle. The Model H in particular, is regarded by many as having been the first "modern motorcycle". Introduced in 1915 it had a 550cc side-valve four-stroke engine with a three-speed gearbox and belt transmission. It was so popular with its users that it was nicknamed the "Trusty Triumph." Postwar Postwar By 1920, Harley-Davidson became the largest manufacturer, with their motorcycles being sold by dealers in 67 countries. Amongst many British motorcycle manufacturers Chater-Lea with its twin-cylinder models followed by its large singles in the 1920s stood out. Initially, using converted a Woodmann-designed OHV Blackburne engine it became the first 350 cc to exceed 100 mph (160 km/h), recording 100.81 mph (162.24 km/h) over the flying kilometre during April 1924.[7] Later, Chater-Lea set a world record for the flying kilometre for 350 cc and 500 cc motorcycles at 102.9 mph (165.6 km/h) for the firm. Chater-Lea produced variants of these world beating sports models and became popular among racers at the Isle of Man TT. Today, the firm is probably best remembered for its long-term contract to manufacture and supply AA Patrol motorcycles and sidecars. By the late 1920s or early 1930s, DKW in Germany took over as the largest manufacturer. BMW motorcycles came on the scene in 1923 with a shaft drive and an opposed-twin or "boxer" engine enclosed with the transmission in a single aluminum housing. By 1931, Indian and Harley-Davidson were the only two American manufacturers producing commercial motorcycles. This two-company