Douglas was a British motorcycle manufacturer from 1907 - 1957 based in Kingswood, Bristol, owned by the Douglas family, and especially known for its horizontally opposed twin cylinder engined bikes and as manufacturers of speedway machines.

History
The brothers William and Edward Douglas founded the Douglas Engineering Company in Bristol in 1882. Initially doing blacksmith work, they progressed to foundry work, and then acquired the flat twin design of W. J. Barter, the founder of Light Motors Ltd. Barter had produced his first single-cylinder motorcycle between 1902 and 1904, and then a 200 cc horizontal twin called the Fair but the Light Motors Ltd. failed in 1907 and was taken over by the Douglas family.

From 1907 they sold a Douglas 350 cc version. In 1915 the engine was placed lengthways in the frame with belt final drive, and electric lighting. During WWI Douglas was a major motorcycle supplier, making around 70,000 motorcycles for military use.

In the 1920s Douglas built the first disc brakes, and had a Royal Warrant for the supply of motorcycles to the Princes, Albert and Henry.

Douglas motorcycles also became popular in dirt track racing and initially the 1923 RA model with disc brakes was favoured. This prompted Douglas to build specific dirt track models. These bikes gradually increased in size and power with 500 cc and 600 cc engines fitted to the DT5 and DT6 Dirt Track models in the late 1920s and early 1930s. The engines had hemispherical heads and a short rigid forged crankshaft. They dominated dirt track racing for about three years. In 1929, the most successful dirt racing year, 1,200 Dirt Track motorcycles were sold.

The Endeavour, a 494 cc shaft drive model came out in 1934. Like other companies of the time, they were struggling, and attempting to diversify into other modes of transport. In 1935 they were taken over by BAC, Bond Aircraft and Engineering Company.

Motorcycle production continued into WWII and was extended to generators. In 1948, not long after the war, Douglas was in difficulty again and reduced its output to the 350 cc flat twin models. The 1955 350 cc Douglas Dragonfly was the last model produced. Westinghouse Brake and Signal bought Douglas out and production of Douglas Motorcycles ended in 1957.

Douglas continued to import Vespa scooters into the UK and later imported and assembled Gilera motorcycles.

Motorcycle Racing
Douglas had some success in motorcycle racing and trials events. Twelve Douglas motorcycles were entered in both the Junior TT and Senior TT, and another three were in the sidecar race during the 1923 TT. This gave Douglas their first Isle of Man TT victories. Tom Sheard won the 500 cc Senior TT and they won the first ever Isle of Man sidecar race with Freddie Dixon while Jim Whalley had the fastest lap in the Senior TT with a time of just under 60 mph during a wet race. A Douglas also placed third in the Junior TT that year. Later in 1923 Jim Whalley won the French Grand Prix, a distance of 288 miles, and another Douglas won the 1923 Durban-Johannesberg Marathon race; a remarkable achievement by Percy Flook on a 2.75 hp machine with an average 43 mph for 430 miles. 1923 also saw Jim Whalley win the Spanish 12-hour race and Alec Bennett won the 1923 Welsh TT race.

This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Douglas (motorcycles)"