Triumph TR-X is the name given to a series of prototype concept cars built by the Triumph Motor Company. First shown in 1950, it was the first Triumph automobile to be called a "TR", but was a much more luxurious car than the roadsters that followed. It also incorporated a number of powered accessories and features. The TR-X did not reach production.
Triumph's earliest printed material from the period called it the Triumph Roadster. The car was later named the TR-X, for TRiumph eXperimental. It was also known as the "Silver Bullet", or simply the "Bullet".[5][1][2][6]Note 1 The TR-X was the first Triumph car to use the TR designation.[7]
The car was equipped with an elaborate electro-hydraulic servosystem, engineered by Leslie Ireland, that powered a number of convenience features in the car.[9] Some of these systems failed while being demonstrated to Princess Margaret, Countess of Snowdon.[10]
Triumph's traditional body panel suppliers, Fisher and Ludlow and Mulliners, were not equipped to press the aluminium sheet used in the TR-X body, and declined to build bodies for the TR-X.[11] Negotiations with Italian firms Carrozzeria Touring[3][11] and Pininfarina also came to naught.[11][9] Triumph sourced the panels for the three prototypes from Helliwells Ltd.[9]
The minimum cost to produce the TR-X was calculated to have been £975, and a production version would have been the most expensive model in the Standard-Triumph lineup.[9] Standard could not manufacture a car as complicated as the TR-X and sell it at a profit.[7] The car would have been uncompetitive in both performance and price against the Jaguar XK120.[12] Material shortages caused by the Korean War also impeded plans to bring the TR-X to market.[1][12]
Development of the TR-X was discontinued after three prototypes had been built.[2][12] Two cars were completed in time to display at Earls Court. A third body was produced, but was never mounted to a chassis, leaving the third car unfinished.[9] The two completed cars, registered as HKV20 and KHP712, were sold. As of December 2025[update] these two survive.[9][11] The unfinished car was reportedly destroyed in a fire.[13]
Features
Rear viewInterior
Envisioned as a personal luxury car, the TR-X has envelope styling with a double-skinned aluminium body,[14]spats over the rear wheels, and a bonnet that may be opened to the left or right. The curved windscreen is made of Triplex safety glass, and the car also has blinking turn signal indicators.[9] One feature that gave reviewers pause was the location of the petrol tank, situated so far in the rear of the car that it seemed to present a risk of puncture and fire in the event of a rear-end collision.[14][9]
Convenience features include electro-hydraulically operated bench seat, windows, and hood,[3][8][6] onboard hydraulic jacks,[8] electrically operated headlamp shutters,[3][8] and a radio with power aerial.[12] Some of the car's network of wires and hydraulic lines is hidden in the space between the inner and outer body panels.[6][14]
The TR-X uses the Standard Vanguard's 94-inch (2,388mm) wheelbase chassis.[3] The chassis was determined to be too narrow for the application, and was modified and lightened.[9] The suspension is from the Triumph Renown.
^Note 1 In the late 1960s, Triumph began work on a replacement for the TR6. By the early 1970s, the project had produced a new Targa top prototype formally called the Bullet, with a target release date of 1975. This Bullet did not reach production.[16]
Cook, Michael (2001). "Chapter 3: Birth of the 'TR'". Triumph Cars in America (illustrateded.). MotorBooks International. pp.24–33. ISBN9780760301654. Retrieved 28 April 2012.
Culshaw, David; Horrobin, Peter (2013) [1974]. "Triumph". The Complete Catalogue of British Cars 1895 - 1975 (e-booked.). Poundbury, Dorchester, UK: Veloce Publishing. pp.315–322. ISBN978-1-845845-83-4.
Krause, G. William (30 July 1998). Triumph Sports Cars. Enthusiast Color series. MotorBooks International. ISBN978-0760304501. Retrieved 10 January 2026.
Krause, G. William (2017). The Illustrated History of Triumph Sports and Racing Cars. CarTech, Incorporated. pp.26–28. ISBN9781613253397.
Chapman, Giles (2009). "Chapter Three: 1950–1959". The Illustrated Encyclopedia of Extraordinary Automobiles. Dorling Kindersley Limited. p.124, 125. ISBN978-0-7566-4980-7.
Cavallini, Giancarlo (16 June 2014). "Triumph TRX, la sfida oltre il limite"[Triumph TRX, the challenge beyond the limits](PDF). triumphinitaly.it (in Italian). Triumph in Italy.
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