BMW 503

Hanns Grewenig, sales manager of BMW, repeatedly requested the development of a sports car based on their 501 and 502 luxury sedans.[6] In early 1954, influenced by the public reaction to Mercedes-Benz 190SL and 220 SC show cars in New York in February 1954, the management of BMW approved the project.[7]

Max Hoffman, an influential automobile importer in the United States, saw early design sketches by BMW's Ernst Loof, and suggested to industrial designer Albrecht von Goertz that he should submit design proposals to BMW.[8][9] Based on these proposals, BMW contracted Goertz to design the 503 and 507 in November 1954.[10]

The 503 was a 2+2 grand tourer that was available as either a coupe or a convertible. It was noted for having a cleaner and more modern design than the "Baroque Angel" 501-based sedans.[11] The convertible version of the 503 was the first European convertible with an electrically operated top.[12]

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  BMW 503 coupe
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  BMW 503 convertible
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  Interior

Tasked with designing rolling chassis for two cars while using as much as possible from the existing 502 sedan, engineer Fritz Fiedler designed two versions of a new ladder frame, one with the same wheelbase as the 502, and one with a shortened wheelbase. The long-wheelbase version was used in the 503.[2] Both cars used the steering system and a variant of the front suspension system from the 502; the 503 also used the 502's rear suspension.[3] As originally designed, the 503 used the 502's remote gearbox placement and shift linkage.[2] Both cars used the braking system developed for the 3.2 sedan, using drum brakes with vacuum assist.[3] All 503s were configured for left hand drive.[13]

Both cars used the 3.2 L version of the 502's V8 engine developed for the 3.2 sedan, but with two carburetors and with an improved lubrication system using a chain-driven oil pump. The 503's V8 had a compression ratio of 7.5:1 and yielded 140 bhp (104 kW; 142 PS) at 4800 rpm.[3][9]

The 503 had sixteen inch wheels and standard final drive ratio of 3.90:1,[2] A final drive ratio of 3.42:1 was optional.[3] Acceleration of the 503 from standstill to 100 km/h (62 mph) had been measured at 13 seconds; the top speed of the 503 is about 115 miles per hour (185 km/h).[5]

In September 1957, the 503's drivetrain was revised. The gearbox was bolted to the transmission and the shifter was moved from the steering column to the floor.[4][5][12][13]

Hoffman had wanted BMW's sports and GT cars to be positioned between Triumph's sports cars and the Mercedes-Benz 190 SL,[2] at a selling price close to US$5000.[1] He told BMW he would order thousands of their sports cars at a purchase price of DM12,000.[14] After its introduction at the Frankfurt Motor Show in September 1955, the 503 began production in May 1956 with a selling price of DM29,500, while the 507 roadster sold for DM26,500 when it began production seven months later.[1]

While a minority, such as Battista "Pinin" Farina's, felt the 503 was superior in design to the 507,[1][9] the 503 was largely overshadowed by it.[1][11][12] However, while neither the 503 nor the 507 sold well enough to earn a profit,[15][16] the larger, heavier, plainer, more expensive 503 sold 412 units to the 507 roadster's 253.[12][17] 139 of the 503s made were convertibles.[4] Production ended in March 1959.[1]

The 503 was BMW's first postwar sports coupe.[18] It was replaced by the Bertone-bodied BMW 3200 CS in 1962.[19][20]

A 1956 BMW 503 Cabriolet with Portuguese plates was driven by the George C. Scott character in the 1971 movie The Last Run.

A 1957 BMW 503 Coupé appears in the BBC drama Father Brown, episode 2, series 4, The Brewer's Daughter, first broadcast January 2016. That car was right hand drive.