Mercedes-Benz 540K

Mercedes-Benz 540K at a glance

From the SSK to the 500K and 540K

The W29 family was the touring successor of the SS and SSK sports cars. The 500K appeared at the Berlin Motor Show in February 1934 and took over the independent suspension of the Mercedes-Benz 380 introduced a year earlier. The "K" stands for Kompressor, the supercharger. Compared with the S, SS and SSK roadsters, the new cars were more comfortable and handled better. English Wikipedia lists hydraulic brakes, a 12-volt electrical system, safety glass, electric windscreen wipers, power door locks and turn indicators as standard on the 500K.

The 540K followed in October 1936. Its engine was enlarged from 5,018 cc to 5,401 cc, which German Wikipedia says added about 11 kW (15 PS) without the supercharger and 15 kW (20 PS) with it. The frame changed too: oval-section tubes replaced the girder-like frame of the 500K, a lighter design influenced by the Silver Arrows racing programme. The planned 580K, with 5.8 litres, was abandoned in 1939, probably after one car was built. Our history of Mercedes-Benz places these cars in the company's wider story.

Supercharged straight-eight

The engine is an overhead-valve straight-eight with one gear-driven side camshaft and water cooling. Twin pressurised updraught carburettors feed it. The Roots supercharger runs only when needed: the driver could engage it for short periods, or it cut in automatically when the accelerator was pressed to the floor.

English Wikipedia gives 86 kW (115 hp) and 130 kW (180 hp) for the 540K; the kW figures above are German Wikipedia's. The 500K could use up to 30 litres per 100 km at full performance. At 2,700 kg for the heaviest bodies, 132 kW works out at about 49 kW per tonne, or about 20 kg per kW; our power-to-weight calculator makes the comparison.

Chassis and suspension

Each wheel was located on its own with a coil spring and damper, which English Wikipedia calls a world first for the 500K. The front used double wishbones and the rear a double-joint swing axle. Brakes were hydraulic, with vacuum assistance on the 540K. The gearbox had four speeds until 1938, with synchromesh on the top three, and five from 1939.

Bodies: Cabriolet A, B, C and the Spezial-Roadster

Most W29 cars were bodied at Sindelfingen; only 70 were delivered as bare chassis for independent coachbuilders. The delivery list for both models shows how the range sold:

The list adds up to 760, one fewer than the 761 cars of the production total. The Spezial-Roadster, launched in 1936 on the short chassis with the engine set back, was the most carefully built body. English Wikipedia says 32 were built on the 540K, and the 500K count includes 29 Special Roadsters. The streamlined Autobahn-Kurier was built six times; one, once owned by Reza Pahlavi, is in the National Car Museum of Iran.

Armoured cars and famous owners

The long special chassis carried armoured cars for the leaders of the Nazi state. English Wikipedia counts 12 extended six-seat convertible saloons with armour. After the attempt on Reinhard Heydrich's life in Prague in May 1942, armoured cars were restricted to ministers and leaders of allied states; 20 armoured two-door saloons were ordered in 1942 and 17 more late in 1943. One was given to Ante Pavelić of the Independent State of Croatia and was later used by Josip Broz Tito; German Wikipedia places it in the Technical Museum in Bistra, Slovenia, and another armoured 540K in the National Technical Museum in Prague.

Hermann Göring ordered a 540K in 1937 in Luftwaffe blue with armour plating and bulletproof glass, nicknamed the "Blue Goose". Soldiers of the US 101st Airborne Division found it at Berchtesgaden on 4 May 1945. It served Maj. Gen. Maxwell Taylor, toured the USA on a victory bond tour and was auctioned by the US Army in 1956. After the 1956 auction the car passed to Jacques Tunick of Greenwich, Connecticut, and in 1958 to the veterinarian George Bitgood Jr., who had it painted black and showed it only once, at the 1973 county fair in Durham, Connecticut. In 2002 it was sold to Carnlough International Limited of Guernsey, with an agreement to restore it as found at Berchtesgaden. Jack L. Warner of Warner Brothers was another 540K owner.

Special bodies were made for other heads of state too. German Wikipedia lists an Erdmann & Rossi body of 1935 on a 500K for King Ghazi I of Iraq, another Erdmann & Rossi 540K of 1938 and a streamlined 540K. English Wikipedia notes that the factory employed 1,500 people to build the 540K. A 540K Spezial-Roadster appears in the German film Meine Freundin Barbara, and English Wikipedia's 500K article notes that Cruella de Vil's car in One Hundred and One Dalmatians strongly resembles a 500K Cabriolet.

Which 540K to look for

• For the design: the Spezial-Roadster, with only 32 built on the 540K; German Wikipedia lists two of them among record auction sales in 2008 and 2012.
• For touring: a Cabriolet B, the most common body with 296 delivered across both models.
• For a two-seater: the Cabriolet A on the short chassis, 116 built.
• For lower cost: the earlier 500K, with the same chassis concept and 118 kW (160 PS).

The record sales were quoted in non-euro currency, so prices are not given here. Later Mercedes sports cars are covered in our article on the Mercedes-Benz 300 SL, and current and past models are in the Mercedes-Benz catalogue.

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