In 1956 and 1957, BMC gave a mid-term facelift to several of the best-selling models, and in this process the A50 became the A55. Although clearly still based on the design of the original A50, the car was demonstrably different and better in some respects.
The new car was announced in February 1957 and was unchanged, mechanically, from the 1957-model A50 which had been on sale for four months. The major styling change was at the rear, where the sheet metal was new, the original 'cow hips' had gone, and there was a longer and more attractive tail with a lower sill, and an even larger boot than before. To round it all off there was a slightly modified front style and an enlarged rear window, and a rather contrived duo-toned paint job could also be supplied. All these changes had already been seen o nthe rather larger bodyshell of the 1957-model A95 Westminster, so there was nothing unexpected about their appearance.
The engine, which had been slightly uprated for 1957 in the last of the A50s, produced 51bhp, and there was the choice of manual, manual plus Borg-Warner overdrive, or Manumatic transmission.
The A55 (the 'Mk I' title was applied retrospectively after the next generation of A55s arrived in 1959) was in production for two years, and in this time the only important change was that a centre-floor gear-change became optional equipment from April 1958; this, in fact, was the same linkage as planned for use in the next generation of A55s.
Austin A55 Cambridge Mk I specification
As for Austin A50 Cambridge except for:
Produced: Longbridge, 1957-59. 369,616 A55 Cambridges of Mk I and Farina Mk II types built.
Engine and transmission: 51bhp at 4,250rpm; 81lb ft at 2,000rpm. Optional centre-floor gear-change from spring 1958.
Dimensions: Length 13ft 10.9in; unladen weight (approx) 2,325lb.
Distinguishing features from previous model: Lengthened tail and new rear style, wraparound window, Manumatic transmission option.
Typical performance: Maximum speed 75mph; 0-60mph 31.8sec; standing 1/4-mile 23.3sec; overall fuel consumption 34mpg.
Launch Price: £678
Fate: Discontinued in 1959 in favour of all-new Farina A55 Cambridge model.
Source: "The Cars of BMC" - Graham Robson (Motor Racing Publications, 1987)