- Sophisticated chassis with independent suspension at the front and DeDion axle at the rear
- A longer wheelbase facilitated larger body variants
- Special-protection variants were also available
The creation of the new ‘Grand Mercedes’ with the internal designation W 150 began at around the end of 1936 and can be attributed to two circumstances: on the one hand the increased demand from industry and government circles for a more modern premium vehicle, and on the other hand the realisation that the existing ‘Grand Mercedes’ model with its conservative suspension including rigid axles at the front and rear plus a chassis of the type found in the very early days of the automobile no longer met the standards laid down by Daimler-Benz AG.
There was also the fact that by then the entire range of passenger cars and racing cars – with the exception of the Nürburg model – had been changed over to designs which included front and rear independent suspension and that since 1931 when it built the Model 170, Mercedes-Benz had been a major protagonist in the arena of advanced passenger car chassis. Daimler-Benz was even already appearing on the international stage as a licensor for the progressive front suspension with two trapezoidal links and coil springs. Even the American motor industry, which tended to be more reserved in such matters, was now using this front suspension.
It was above all a challenge facing design boss Max Wagner: to come up with an up-to-date chassis for the new ‘Grand Mercedes,’ and the experience gained when redesigning the W 125 and W 154 racing cars proved valuable to him. As was the case with the latter models, for the new ‘Grand Mercedes’ he used a chassis made of pipes as a longitudinal member. At the front axle this had trapezoidal links of unequal length and coil springs, and at the rear what was known as a parallel wheel axle – a DeDion axle with coil springs. The thrusts at the rear axle were absorbed by V-shaped front-facing members, which were pivoted on the centre transverse pipe.
The outer longitudinal members made of pipes were curved far downwards in front of the rear axle in order to achieve a low centre of gravity. The longitudinal members were connected to six transverse pipes which were pierced and welded with the longitudinal members. In conjunction with the large shock course for the spring, this torsionally rigid design with bending resistance resulted in excellent road holding, which was unusual amongst such big and heavy luxury cars.
This was illustrated by a quotation from the only test report of the time, which appeared on 23 May 1939 in the British magazine ‘The Motor’: ‘Normally a limousine of this size will not be driven in a spectacular manner. We did some fast travelling on winding roads and the general standard of handling and road holding is undoubtedly very good indeed. The car holds its course admirably through fast bends, and the absolute rigidity of the tubular chassis is well reflected in the road holding. Although no ride control is employed, the suspension system provides a good combination of soft riding in town with steady cornering and freedom from excessive roll on the open road, and the whole car gives an impression of considerable stability.’
But it was not merely the chassis design that made such a difference compared with the predecessor – the larger dimensions played a part too. The wheelbase increased by 130 millimetres (5.1 in), the track width at the front increased by 100 millimetres (3.9 in), and at the rear by as much as 150 millimetres (5.9 in). And so the task of the body designers working under Hermann Ahrens was to create lighter, more spacious bodies, whose length grew by an extra 400 millimetres (15.7 in), making them precisely 6 metres (236 in) long.
But the vehicle weight also increased with the size. Whilst the brochure for model series W 07 still referred to 2700 kilograms (5952 lbs), the weight for model series W 150 went up to between 3400 kilograms and 3600 kilograms (7496 lbs and 7937 lbs) – also according to the brochure. And in some cases it did not stop there. For the special-protection version as a six-seater, 4400 kilograms (9700 lbs) of mass had to be set in motion – as much as 4550 kilograms (10031 lbs) in the case of the even more heavily armoured four-seater. The engine output was also increased for these weights. In the naturally aspirated version the engine output increased by 5 hp (3.7 kW) to 155 hp (114 kW), with a switched-on positive-displacement blower by 30 hp (22 kW) to 230 hp (169 kW). The shafts of the outlet valves were filled with sodium salt for better cooling.
The three-speed transmission from the predecessor with engageable overdrives did not survive in the successor either. It was superseded by a four-speed transmission with a fifth gear as a high-ratio overdrive. So as not to be punished by shorter refuelling intervals with the increased engine output and significantly higher weights, the tank capacity went up from 120 litres to 195 litres (31.7 to 51.5 US gal). For what was the world’s largest representative vehicle when it entered the market Daimler-Benz gave the top speed as 170 km/h (106 mph), though this was drastically cut to 80 km/h (50 mph) for the heavily armoured versions with their bullet-proof twenty-chamber tyres.
This is what ‘The Motor’ wrote about the performance and top speed of the conventional Pullman saloon in 1939:
‘Changing gear gently, without the second-saving brutality that has normally to be employed for test purposes, it proved possible to cover the standing quarter-mile in 21 seconds. From a standstill to 50 mph took 12.2 secs. and to 60 mph. 17 secs., which suggests the standard of performance available without necessarily indicating the absolute maximum results obtainable. Cutting the blower in for a quarter of a mile sufficed to raise the speed from 75 mph to 87 mph, demonstrating its value in maintaining high averages after temporary checks. Timed over a quarter of a mile, the car clocked 100 mph. With some ease, carrying four people; indeed, it was accelerating along the Railway Straight at Brooklands. The speedometer is very nearly accurate erring slightly on the side of slowness lower down the range, and the ultimate readings obtained suggest that the absolute maximum speed is in the region of 108 mph, a truly impressive velocity for an eight seater limousine weighing 3 tons.’
The career of the ‘Grand Mercedes’ (W 150) unarguably suffered due to the Second World War, which began shortly after production started. This was also borne out by the body variants produced: the open-top touring cars favoured by the government dominated, in stark contrast to the predecessor model, for which more civilian bodies had been made, such as cabriolets and Pullman saloons.