This BMW is not known even to the most die-hard fans. The reason for this lies mainly in the car itself: only 412 examples of the 503 were produced. It was launched on the market 70 years ago. Let's look back. Its story begins a little earlier.
At the 1955 Frankfurt International Motor Show, BMW presented two new models, the 503 Coupé and the 503 Cabriolet, which were positioned above the existing 501 and 502 sedans. Both versions were designed as luxury 2+2-seaters and were technically closely related to the BMW 502 3,2 Liter Super. The chassis, drivetrain and much of the technology were taken from that model. Under the newly developed bodywork, an eight-cylinder V-engine made of light alloy with a displacement of 3168 cubic centimeters and an output of 140 hp at 4800 rpm worked.
The body design was the work of Albrecht Graf von Goertz, who was also responsible for the BMW 507. Following preparatory work by Kurt Bredschneider, Goertz developed both the BMW 503 coupe and convertible in a short period of time. Both vehicles were built in the form of a pontoon with a classic BMW and clearly differed from the 501 series sedans, which still had a strong pre-war design. The BMW 503 appeared more realistic, clear and modern, marking a stylistic turn in BMW's range at the time.
The BMW 503 had its public premiere at the IAA Motor Show in September 1955. Together with the BMW 507, both models became the most notable vehicles at the show. The Roadster was dubbed the “Dream of the Isar”, while the Coupé and Cabriolet of the 503 were seen as luxury touring cars, primarily intended for the American market. For Goertz, these models represented an international breakthrough as an automobile designer.
Series production began in May 1956. Both the coupe and convertible were hand-built. The body consisted of a steel frame, which was intended to protect the passengers in the event of an accident. The front wall, inner fenders and reinforcements were also made of steel.
The exterior body parts, such as the bonnet, doors and boot lid, are made of aluminium-magnesium alloy, as pure aluminium was deemed too soft in the prototypes. The dashboard is also made of solid aluminium. The bodywork was originally planned to be produced by Baur, but was eventually carried out at the BMW factory. Contrary to later claims, neither the design nor the production of the 503 bodywork was carried out by Bertone.
Technically, BMW largely uses existing components. Engineer Fritz Fiedler develops two versions of the new frame based on the 502. A version with an unchanged wheelbase is used for the BMW 503. The front and rear axles and the steering also derive from the 502. Power transmission is initially carried out via a remote-controlled gearbox with a gearshift on the steering wheel and a gearshift located under the front seat. The braking system initially operates with drum brakes and a brake booster. From 1957, BMW equipped the front axle with disc brakes as standard. This change was made, among other things, based on recommendations from John Surtees, who himself drove a BMW 507.
The engine enabled performance that was exceptional for a luxury car from the 50s. The BMW 503 accelerated from 0 to 100 km/h in 13,3 seconds and reached a top speed of 190 km/h. The side air outlets, so-called gills, were supposed to reduce heat build-up in the engine, similar to the BMW 507. Due to thermal problems, BMW built some vehicles with additional air vents in the front wings at the request of customers. Goertz later confirmed this change from a design perspective.
The convertible has a special place in this series. It is the first European series car with an electro-hydraulic hood and electric windows. However, the number of vehicles produced is very small. From May 1956 to the end of production in the spring of 1960, only 412 BMW 503s were produced. Of these, 273 were coupés and 139 convertibles. Three coupés and three convertibles were produced with right-hand drive specifically for the British market.
During production, BMW distinguishes between two series. The 1 Series vehicles have a gear lever on the steering wheel, hydraulic window lifts and a hydraulically supported roof. The ashtray is located under the dashboard, the side trim strips are slightly curved upwards at the rear. The 2 Series is equipped with a gearshift lever with a gearbox directly attached to the engine, electric windows and a modified interior. The ashtray is moved next to the radio speaker, the trim strips are now flat. The roof remains hydraulically operated.
The price of the BMW 503 was around 29.500 to almost 30.000 German marks, a level significantly higher than the price of most modern vehicles. This meant it cost about twice as much as originally planned. Neither the BMW 503 nor the BMW 507 could cover their development costs. Nevertheless, the 503 model consolidated the brand's image as a manufacturer of high-quality and technically sophisticated cars.
The last coupe produced has chassis number 69412, and the last convertible has chassis number 69408. Today, both versions of the BMW 503 are among the rarest and most sought-after classic models of the brand.
