In the 1920s, ambitious automotive designs were characterised by three things: a move away from the rigid rear axle towards independently suspended wheels; a rear- or mid-engined configuration with a compact drive unit respectively behind or in front of the rear axle; and a streamlined body – or rather what went by that name in those days.
The pace was set by pioneers such as Edmund Rumpler, Hans Ledwinka, Gustav Röhr and the technically committed chief editor of the magazine “Motor Kritik”, Joseph Ganz, who was a strong advocate of the small streamlined car.
Hans Nibel and Max Wagner also belonged to the group of open-minded engineers willing to abandon old ways in an endeavour to try something new.
Having worked intensively with innovative design ideas at Benz & Cie. in the early 1920s, and would later play a leading role at Daimler-Benz in Stuttgart-Untertürkheim in restructuring the passenger car range.
At Benz in 1922, they embarked on the development of a state-of-the-art mid-engined racing car. With its avant-garde styling, the vehicle, known only to insiders under its official name of Benz RH (“Rennwagen Heckmotor” or rear-engined racing car), was to make automotive history as the Benz teardrop racing car, named for its distinctive shape.
On 9 September 1923, Benz achieved considerable success at the European Grand Prix in Monza, when two teardrop racers finished fourth and fifth despite their inferiority to competitor cars in terms of power output.
What seems a rather modest accomplishment in the usual world of the race track was in reality a great triumph.
That was also the view of the race organiser, who presented Max Wagner with the prize for the most unconventional racing car in the starting line-up.
The experience gained with the teardrop racing car was to benefit Daimler-Benz in the early 1930s, when challenging economic times called for a broadening of the sales programme to include competitively priced small cars.
Unveiled in 1931, the 170 (W 15) boasted so-called swing axles, i.e. independently suspended front and rear wheels, but otherwise conformed to the conventional layout with a front engine and rear-wheel drive.
The same year saw the launch of the 1.2‑litre W 17, one of the first Mercedes-Benz rear-engined prototypes. The air-cooled, horizontally opposed, four-cylinder overhead-valve engine developed output of 25 hp, highly impressive by the standards of the day.
The W 17’s engine concept anticipated a number of key features that later contributed to the success of the Volkswagen. However, despite weighing over a tonne, the vehicle was equipped with only a three-speed transmission.
While opting for a rear swing axle, the designers decided in favour of a rigid front axle with semi-elliptical springs.
The few remaining photos of this prototype show two different body variants: an angular saloon with, in the words of a well-known motoring author, “all the charm of a coal box”, and a streamlined fast-back saloon with thoroughly attractive styling. Neither of the two variants of the W 17 went into production.
Soon afterwards, the designers in Untertürkheim made another attempt, which this time made it to the production line. The fruit of this labour, the Mercedes-Benz 130, was unveiled in March 1934 at the International Motor and Motorcycle Show in Berlin together with the 500 K Autobahn-Kurierwagen.
At the time of its launch, the 130, known internally as the W 23, was not just Daimler-Benz’s smallest series-produced passenger car and the company’s first rear-engined model, it was also the world’s first mass-produced rear-engined automobile if one disregards the early vehicles constructed by Karl Benz and Gottlieb Daimler in the 19th century.
Nevertheless, its model designation never officially included the “H” (for “rear engine”), even this often found its way into internal documents.
The 130, also designed by Hans Nibel and Max Wagner, sported a tubular backbone chassis that was forked at the rear to accommodate engine and transmission, the four-speed transmission and the engine being fore and aft of the rear axle respectively.
The four-cylinder in-line powerplant conformed to Daimler-Benz’s customary design principles for road vehicles. The water-cooled engine featured standing valves while delivering a power output of 26 hp.
This engine formed the basis for subsequent generations of four-cylinder in-line units as far as the M 136, which was used in the 180 as late as 1957.
The front wheels were independently suspended with two transverse leaf springs. At the rear, the 130 sported a swing axle with a single coil spring on either side.
At the time of its launch, the 130 was available as a bare chassis, two-door saloon, two-door convertible saloon and two-door tourer. In 1934/35, some variations of the Kübelwagen were manufactured.
With the military failing to show any enthusiasm for this product, a civil variant called the 蕒 Reichsautobahn” was built in the form of an open two-door tourer with externally mounted folding spade and other useful accessories.
The rear-engined vehicle’s handling soon led to a heated debate. With an axle load distribution of 35% at the front to 65% at the rear, the vehicle proved extremely tail-heavy in on-road use.
Hence, as early as 1935, the 130 was relaunched in revised form following over one year of development. The improvements related mainly to the body as well as the interior equipment and appointments.
Prominent interior features included two large circular instruments in front of the driver – speedometer and instrument cluster – with their bright dials, in addition to a clock in the glove compartment lid.
The rubber mats were replaced by with end-to-end carpets, while the front seats now sported superior upholstery and could be adjusted during driving.
The footwell was provided with ventilation flaps, which were recognisable from the outside by two slits to the right and left above the front wings.
Two-tone paintwork now came as standard, the wings being optionally available in black or in the second vehicle colour.
Already before the start of the new model year, the 130 had already been equipped with a Vigot jack, and the front luggage compartment hood had been so that it no longer embraced parts of the front side wall.
Concerns over the vehicle’s handling were addressed by changes to the tuning of springs and shock absorbers, modified front wheel camber and less direct steering.
Remaining stocks of the original variant continued to be available as the “Model 34” and were included in the price list up until July 1935.
Whereas the prices of the saloon and convertible saloon versions were reduced by RM 225, the “Model 35” cost an extra RM 480 and RM 500, respectively.
When this facelift failed to deliver the hoped-for boost in sales, the need for a successor model could no longer be ignored. October 1935 brought a further technical modification that allowed the fuel cock to be operated from the driver’s seat.
At the same time, the price of the so-called “Autumn Model 1935”, which did not yet include this new feature, was lowered by RM 580 and 600, respectively.
However, neither this measure nor an additional price reduction just two months later for the “Winter Model 1935” was able to produce the desired growth in sales for the 130.
In February 1936, the unconventional 1.3-litre vehicle gave way to the more powerful and, in many respects, redesigned 170 H. The 130 continued to feature in the price list as a discontinued model until February 1937.
A total of 4 298 vehicles were produced between November 1933 and April 1936.
In 1933/34, the 150 (W 30) was developed as a two-seater sports saloon for use in competitions. In its day, it represented a milestone in technological innovation, the importance of which did not become apparent until much later.
Based on the 1.3‑litre unit from the 130, the engine delivered 55 hp, over 100% more than the original product. This was made possible, on the one hand, by raising displacement to the 1.5-litre class limit allowed by the sports regulations.
Also, the standing valves in the 1.3‑litre engine were replaced with overhead valves operated by a spur-gear-driven overhead camshaft. The updraft carburettor gave way to a dual carburettor.
The most significant change compared with the 130, which shared its chassis configuration with the 150, was the use of the mid-engine concept, which still finds application today in sports cars and in Formula 1.
To improve the axle load distribution, the engine/transmission drive package was turned through 180°. Engine and transmission were now fore and aft of the rear axle, respectively.
The 150 sports saloon won four gold medals at the 2000-kilometre endurance race across Germany in July 1934. One of the vehicles was driven by a young driver who, had started out in 1933 as a racing mechanic and, was destined from 1935 onwards to be at the wheel of the legendary Silver Arrows.
This up-and-coming talent was none other than Hermann Lang. The sports saloon’s greatest triumph remained relatively unknown: In the Liège-Rome-Liège Rally at the end of August 1934, having led the field between Rome and Pisa and on reaching the finishing line without penalty points, Hans-Joachim Bernet won the special prize for the best-placed closed-body car.
The sports saloon, which had just two seats and would certainly be described as a coupé in modern terms, be described as a coupé, sold six units in 1934.
With its technical concept, the Mercedes-Benz 150 can, to a certain extent, be considered a legitimate successor to the Benz RH racing car.
At the end of 1934, the competition vehicle served as the basis for developing the 150 sports roadster (W 130), which was exhibited at the International Motor and Motorcycle Show in February 1935, where it caused quite a sensation.
Despite, or perhaps precisely because of, its unconventional technical concept and atypical styling for a Mercedes-Benz, the vehicle did not make it into series production.
There is a difference of information on the number of units produced. Whereas the Sindelfingen body production statistics indicate just five units, the order books show that only four exemplars were shipped. The Mercedes-Benz Museum is in possession of one of those sports roadsters.
The 170 H (W 28), which superseded the 130, made its debut in February 1936 at the International Motor and Motorcycle Show in Berlin together with its sister model, the 170 V.
This was the first and – as far as passenger cars are concerned – only time that the “H” (for “rear engine”) was officially used in the model designation.
This was necessary to distinguish the rear-engined model from the 170 V, which, while of identical displacement, had its engine at the front.
The 170 H and 170 V had originally been designed with a 1.6‑litre engine. Based on the 1.3‑litre engine, this power unit, under development since 1933, had originally been intended to power the rear-engined model from as early as 1935.
The increased displacement, achieved by widening the bore and lengthening the stroke, served above all to raise the torque while the power output remained unchanged.
The body of the 170 H, with more harmonious and balanced lines than its predecessor, met with general approval.
Surviving photos of the prototype, still powered by the 1.6‑litre engine, show a number of detailed differences from the later production version. The front part of the side walls reveals slightly different positioning of the three footwell ventilation slits.
Other significant distinguishing marks are the size of the direction indicators and the design of the bonnet. In the prototype, the engine lid is in snug, angular contact with the bodywork arches and has 2 x 8 air slits, whereas the engine lid on the series-produced version is generally smaller with 2 x 21 slits and rounded corners.
On the prototype, the two bordered pairs of ventilation slits below the rear window are provided with a cover plate, while this feature is absent on the production model. Further differences relate to the bottom part of the engine lid and – related to it – the position of the rear number plate.
The technical concept of the backbone chassis with its rear fork to accommodate the rear engine, was copied from the 130. The 170 H differed from the 170 V not just through its avant-garde looks.
It also offered superior performance, reduced engine noise thanks to the rear-mounted engine and – exceptional for those times – a standard-installed heater. In addition, its fourth gear was in the form of an overdrive/economy gear.
Its compressed-air cooling was an attention grabber: a blower wheel driven by the alternator shaft forced the air through the radiator, which was able to be made smaller than usual owing to the forced air supply.
What the 170 H had in common with its predecessor was a still noticeable tendency to oversteer due to the unfavourable axle load distribution of the rear-engined vehicle.
Although meticulous chassis tuning had yielded a significant improvement compared with the 130, handling still took some getting used to.
From 1938, the 170 H sported double-acting shock absorbers and the instrument panel was provided with two dials, one for water temperature and the other for oil temperature.
Like its predecessor, the strictly two-door 170 H was available in saloon and convertible saloon versions. An open tourer was not included in the line-up. Between July 1935 and October 1939, a total of 1,507 units of the 170 H were built.
Success on the sales front was hindered to some extent by the lower-priced, more conservative and, above all, easier-to-drive 170 V.
The 170 H was also used to conduct experiments with low-drag body forms. An experimental vehicle of the Göttingen Aerodynamics Research Institute posted a maximum speed of 146 km/h as the average of three measurements in both directions.
The body in question was designed by engineer Karl Schlör and built by the coachbuilders Ludewig in Essen.