The Triumph Roadster was produced by Britain’s Standard Motor Company from 1946 to 1949. It was first available as the Triumph 1800 Roadster (18TR) from 1946 to 1948 and then as the Triumph 2000 Roadster (TRA) from 1948 to 1949. The 1800 Roadster was designed in the closing days of World War II. Triumph had been bought by the Standard Motor Company in 1944, and the managing director of Standard, Sir John Black, wanted a sports car to take on Jaguar, who had used Standard engines in the pre-war period. Frank Callaby was selected to style the new car. After getting Black’s approval for the general shape, Callaby worked with Arthur Ballard to design the details of the body. Design of the rolling chassis was by Ray Turner. Walter Belgrove, who had styled the pre-war Triumphs and was employed as Chief Body Engineer, had no part in the design.
Early post-war steel shortages meant that the body was built from aluminium, using rubber press tools that had been used making panels for the largely wooden bodied Mosquito bomber that had been built by Standard during the war. The frame was hand welded up from steel tube. The engine was a version of Standard’s 1.5-litre, four-cylinder side-valve design that had been converted to overhead valves by Harry Weslake and built by Standard exclusively for SS-Jaguar before World War II. The Triumph version differed from the Jaguar version in having a 6.7:1 compression ratio instead of the Jaguar’s 7.6:1 and a downdraught Solex carburettor instead of the Jaguar’s side-draught SU. A four-speed gearbox with synchromesh on the top three ratios was used. The tubular steel chassis was a short-wheelbase version of the 1800 saloon, featuring transverse leaf sprung independent suspension at the front and a live axle with semi-elliptic springs at the rear. The rear track was wider than the front by some 4 inches. Brakes were hydraulic.
The body design was anachronistic. A journalist old enough to remember the pre-war Dolomite Roadster that had inspired the car felt that the elegant proportions of the earlier model had been abandoned in favour of a committee-based compromise, “a plump Christmas turkey to set against that dainty peacock … more Toadster [than Roadster]”. The front had large separate headlamps and the radiator was well back from the front between large “coal scuttle” wings. Passenger accommodation was on a bench seat that was claimed to seat three: the car’s 64 inch width helped make a reality of the three-abreast seating, and the approach meant a column gear change was required. The car’s unusual width also made it necessary to fit three screen wipers in a row, an example followed by early shallow windscreen Jaguar E Types. Additional room for two was provided at the rear in a dickey seat with its own folding windscreen: this was outside the hood that could be erected to cover the front seat. Entry and exit to the dickey seat was never easy and a step was provided on the rear bumper. The Roadster was the last production car with a dickey seat.
On test by Autocar magazine in 1947 top speed was found to be 75 mph (121 km/h) and 0–60 mph (0–96 km/h) took 34.4 seconds. Evidently keen to be positive without misleading their readers, the magazine described the maximum speed as “satisfying but not startlingly high”.