Calthorpe began when George W. Hands began manufacture of bicycles in Bordesley, Birmingham in about 1890 and built his first motorcycles at Calthorpe's Barn Street premises in 1910 - one source says they first exhibited at the Stanley Cycle Show in 1909. Initially using JAP and Precision engines, after the First World War they also used Peco, Villiers and Blackburne units. By 1924 they were producing their own 350cc ohv engine, and in 1927 built a 500cc overhead cam model. Only around 100 of these relatively expensive machines were made.
The Ivory series began in 1928 (or 1929) and was very well received with its saddle tank and duplex frame, but by the late thirties the company was in decline and went bankrupt in 1938. Revival attempts occurred in 1939 with Matchless engines, but the war interceded. Another revival attempt in 1945 using Villiers two-stroke powerplants was also unsuccessful.