Calthorpe Motor Co of Cherrywood Road, Bordesley Green, Birmingham made cars and motorcycles from 1904 to 1932.
1910 Stanley Show Report
Calthorpe Motor-cycle Works.
Birmingham. Stand No. 52.
The six Calthorpe models illustrate three different patterns of motor-bicycles. The standard touring machine is fitted with an engine measuring 86nnn. in the bore and 88 in the stroke. This is rated at 3.75 H.P., and we should think this power is by no means over-estimated. The valves are, of generous dimensions and are both mechanically operated. Belt trans- mission is employed with a variable pulley. A Brown and Barlow carburetter and high tension magneto supply the gas and the means for firing it. There is a specially designed cut-out on the silencer. A good deal of care has been bestowed on the tank and its accessories. It is fitted with large, quickly detached tillers, and a combined filter and petrol gauge. Lubrication is effected by a drip feed oil pump. Last, but not least, the frame is designed so as to afford a very low saddle position. Another specimen is similar to the above, but has a side-car attached, and is similarly equipped with as L.M.C. free engine and two-speed gear. Then there is a third with another style of frame even lower than the first. Probably the most interesting of the lot is the new Tourist Trophy model. This has a short stiff frame and rigid stayed front fork. Pedalling gear is, of course, absent, and the foot-rests are adapted to operate a powerful brake on the belt rim. Weight has been studiously reduced while maintaining strength and the horse-power per lb. rating works out very high. The prices are attractive both to the agent and rider, and the company's motto continues to be "Wholesale, and to the Trade only."
1912 They used Precision engines and began to add further models, including a lightweight. Then came a model with water cooling.
1914 The Calthorpe Minor was produced with a 1.25 engine and a two-speed gearbox in the crankcase.
1915-1922 A two-stroke model appeared in 1915 - this used a JAP engine. It continued for 1916 and from then on a 2¾ hp four-stroke and 2½ hp two-stroke, both with Enfield gears were built. These continued well into the post-war years.
1922 The two-stroke also became available with a single speed and belt drive as an option. They were then joined by a 350cc two-stroke with a three-speed Burman gearbox and chain-cum-belt transmission.
1924 The 245cc two-stroke had a three-speed Burman gearbox; the 350cc version was dropped and a JAP was used in sv and ohv forms along with a 147cc Villiers engine.
1925 The all-new 348cc Sports model arrived with own-designed engine, three-speed Burman gearbox, light frame and Druid forks.
1926 A Super Sports version was added.
1927 A 498cc ohc single of their own design appeared.
1928 The company was only using its own engines, with the 348cc in its two forms. The camshaft model was then dropped.
1929 Saw the arrival of their best known model - the Ivory Calthorpe. For this they took the 348cc ohv model, revised and modified it, added a saddle tank and finished the tank and mudguards in off-white.
1930 There was a single-model range. Following the trend of the time, they gave it an inclined cylinder and listed it as Ivory the Second, which then went on to Ivory III.
1932 By now there was the 494cc Ivory IV, and for that year only there was also 247cc two-stroke Ivory Minor.
1933 Only the 494cc model was listed, as the Major.
1934 That model was joined by a 247cc model. Following on came 348cc and competition versions and those continued throughout the decade.
1937 The firm of Pride and Clarke of London had exclusive rights to sell the marque, which had changed its colour to become Red Calthorpe. This change did not boost sales; the firm went into liquidation and was then bought by Bruce Douglas, who moved the plant to his company of that name, in Bristol.
1939 In May of that year, Bruce Douglas announced a three-model range using Matchless engines. A few of these were built before the factory turned to war efforts.
1947 After World War II the name reappeared as Calthorpe-DMW, on a machine using a 122cc Villiers engine. By 1950, this had led to the formation of the DMW marque.
Source: Graces Guide
Quite extensive model information available at calthorpe.info
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