The Mercedes-Benz SSKL, the basis of the winning vehicle at the 1932 Avus race, was a genuine serial winner. This becomes obvious by analysing motorsports vehicles and race results in the late 1920s. Daimler-Benz AG developed the new S model high-performance sports car in 1927. It is based on the Mercedes 24/100/140 PS luxury saloon launched by DMG in 1924, developed by the head designer at the time, Ferdinand Porsche, as well as the model K, which was derived from said vehicle in 1926.

The Mercedes-Benz S model was aimed at wealthy, privately funded drivers and, as a result of its superior potential, also at racing teams. Its design follows the formula of combining a compressor engine with plenty of engine capacity and a durable chassis. Other brands also adopted this principle. Accordingly, the vehicle’s exterior dimensions are impressive. The S model (the abbreviation was short for “Sport”) was the basis for the SS (“Super-Sport”) high-performance sports car dating back to 1928 and the SSK (“Super-Sport-Kurz”, i.e. super sport short), the latter with a smaller wheelbase, which was reduced by 450 millimetres to 2,950 millimetres. As was previously the case with the S model, the SSK also dominated the international racing circus.

However, the competition, most of all from the UK, France and Italy, was strong. Brands including Alfa Romeo, Bugatti and Maserati launched racing cars with new concepts. They were significantly more compact and lighter than the SSK, coped with a correspondingly lower engine output and were more agile. The new designs also preserved tyres better, one of the most significant benefits considering the increasingly higher speeds. However, the SSK continued to compete at the top level and collected numerous, renowned victories.

Evolutionary model: Mercedes-Benz SSKL

For the 1931 season, Mercedes-Benz improved the vehicle with measures to cut its weight and an engine output that had been increased to 220 kW (300 HP): the SSKL was born. However, the model was initially not officially known by this designation, but was simply called SSK or “SSK Model 1931”. The “SSKL” designation only gradually gained popularity. The additional letter “L” was short for “Leicht”, i.e. lightweight, as the vehicle weighed 125 kilograms less than the SSK.

This SSKL evolution stage goes back to Head of Development Dr Hans Nibel and designers Max Wagner and Fritz Nallinger. It did not play a part in the sales range as the measures represented a works modification that was exclusively implemented on a mere four vehicles in Untertürkheim according to exact specifications. Two of these vehicles were registered to the company and used by works drivers Rudolf Caracciola and Hans Stuck. The third specimen was delivered to Count zu Hohenlohe-Bartenstein. The fourth vehicle was handed over to Baron Hans von Zimmermann – the sponsor and cousin of Manfred von Brauchitsch, who had already provided him with the previous vehicles.

The SSKL continued its predecessor’s series of victories. For instance, victories in the 1931 season included Caracciola’s overall win at Mille Miglia in April as the first non-Italian. On 7 June 1931, Caracciola also won the Eifelrennen race at Nürburgring, which astonished experts in light of factors including the considerable tyre issues Mercedes-Benz had and, most of all, the strong competition. A further surprise finished in third place: aspiring, privately funded driver Manfred von Brauchitsch. He also impressively demonstrated the SSKL’s potential and his talent at Nürburgring.

Motorsport in times of the financial crisis

Two months later, on 2 August 1931, the International Avus race took place in Berlin, a distinctive high-speed track. Six of the twelve starting vehicles finished the race. Caracciola claimed the top spot with an average speed of 185.7 km/h. Once again in third place: Manfred von Brauchitsch. The fact that all other vehicles that made it to the finish line were exclusively Bugattis characterised the now difficult position of the SSK/SSKL.

At any rate, the outlook was not great as the world had plunged into a financial crisis and Mercedes-Benz had decided to temporarily cease the motorsports activities. A serious blow, also for Caracciola. He was no longer a works driver of the Stuttgart-based company and was forced to seek a new racing team for 1932 – he found a new employer on the other side of the Alps at Alfa Romeo. However, his start there was anything but easy as regular drivers denied him the status of equal driver – and to assert this, Caracciola’s Alfa Romeo was initially even painted white instead of Italian red. This changed after his first successes and most of all as a result of his fairness towards Tazio Nuvolari at the Grand Prix of Monaco.

Consequently, Caracciola started at the International Avus race in Berlin on 22 May 1932 in an Alfa Romeo and was thus a competitor of the vehicles in which he had been successful only one year prior, in 1931: this gave the race an additional, explosive edge. He was considered the favourite. Two privately registered SSKLs started on the grid. At the wheel: Hans Stuck and Manfred von Brauchitsch who were provided with only very little technical support by the factory. Consequently, for instance von Brauchitsch’s vehicle was given an engine overhaul and a rear axle with a higher gear ratio. These measures had been initiated by racing manager Alfred Neubauer, who was, strictly speaking, taking a break, yet was also on site to supervise the work and provide both drivers with tactical advice. As a result, Mercedes-Benz had not completely stepped down from the action.

Other competitors were strong and fierce. Quite simply, the world’s best racing drivers competed in the best racing cars. The Avus track consisted of two parallel straights with a length of 9.5 kilometres each that were linked by two corners in the north and south to form a circuit. The straights enabled speeds of significantly more than 200 km/h. Back in the day, Avus was the world’s race track enabling the highest speeds.

SSKL with a streamlined body made the headlines

Brauchitsch’s SSKL attracted quite some attention as his vehicle had been equipped with an unpainted and thus silver, streamlined body. It was a practical design by mechanical engineer Reinhard Baron von Koenig-Fachsenfeld: it made the vehicle 20 km/h faster and thus convinced him that von Brauchitsch stood a genuine chance of coming away with the victory.

When the start flag flew in the wind at 4 pm to mark the launch of the main race, around 250,000 spectators at Avus and an even bigger crowd listening on the radio followed the performance of the streamlined SSKL with great excitement and anticipation. The audience had nicknamed the vehicle the “Gherkin”. Drivers and vehicles had to complete 15 laps and thus cover a distance of 294.4 kilometres. Caracciola quickly lived up to his position as the favourite, but von Brauchitsch quickly caught up with him. From the seventh lap onwards it was clear that the race winner would probably be decided between these two drivers. In the eighth lap von Brauchitsch took over as race leader. After the ninth lap a mere five drivers remained in the race – and Caracciola had reclaimed the top spot as a result of his white Alfa Romeo’s better acceleration.

The crowds on the stands were on the edge of their seats and jumped up every time the drivers whizzed past. In his broadcast for Südwestdeutsche Rundfunkdienst AG, based in Frankfurt am Main, radio commentator Paul Laven, one of the first radio reporters for live broadcasts, called the streamlined SSKL that was flying along the straights a “silver arrow”. It was a neck-and-neck race. Each lap, Caracciola, at the wheel of his agile Alfa Romeo, caught up in the corners while von Brauchitsch in his bulky SSKL was hot on his heels on the straights.

Caracciola managed to remain in the top spot until the last lap. But then von Brauchitsch managed to once again overtake him in the southern corner. He defended his lead to the home straight while his compressor engine howled. Then the chequered flag made it clear to him: He’d won the race. After one hour, 30 minutes and 52 seconds for the race distance of 294.4 kilometres and with an average speed of 194.4 km/h, he simultaneously set a speed record over a distance of 200 kilometres. Caracciola crossed the finish line a mere 3.6 seconds later at the wheel of an Alfa Romeo P 3 with an average speed of 194.3 km/h. In third place: Hans Stuber in the Bugatti T 51 at an average speed of 186.9 km/h followed by Hans Stuck in the SSKL with a normal body at an average speed of 185.6 km/h.

The victory made dreams come true

For two people this victory made great dreams come true: 26-year-old Manfred von Brauchitsch broke through as a racing driver and became an acclaimed star. Overnight, he became a household name throughout Europe, making the headlines in daily newspapers. For the 1933 season, he received parts and workshop support from Daimler-Benz. In 1934 he signed his first works contract including a “company vehicle”. Consequently, he was liberated from his constant financial worries for the very first time.

It was the first time that Reinhard Baron von Koenig-Fachsenfeld had proven the effectiveness of his aerodynamics deliberations on a racing car and thus at very high speeds – a milestone in automotive history. The victory suddenly made the Baron well-known to a large audience and sparked an awareness for aerodynamics and the associated effects on motorcars. The success of aerodynamics in the past, for instance with the Benz 200 PS racing car “Blitzen Benz” and the Benz “Tropfen-Rennwagen”, was never quite in the public eye as it was in 1932 within the context of the victory at Avus.

The victory of the “silver arrow” at the Avus race caused vehicle designers to rethink their approach. The vehicle was a genuine game changer: in the era before it, “traditional” racing cars with normal bodies dominated proceedings. Thereafter, the world witnessed the launch into the era of streamlined racing cars – and slowly, but surely, aerodynamics were also established within the context of passenger and commercial vehicles.

On 29 May 1932, a week after the Avus race, von Brauchitsch once again put the new, streamlined racing car on the starting grid of the Eifelrennen race at Nürburgring and finished in fourth place at the wheel of the Mercedes-Benz, ahead of Hans Stuck in the SSKL with a normal body. However, this time Caracciola won the race. His Alfa Romeo was able to demonstrate its advantages around the track with its many corners.

At the end of 1932 the AIACR (Association Internationale des Automobile Clubs Reconnus) motorsports authority, based in Paris, announced a new formula for Grand Prix racing that came into force as of 1934: the cars, without fuel, oil, coolant or tyres, were to weigh no more than 750 kilograms, but otherwise the engineers were not subject to any further restrictions. Mercedes-Benz designed the 750-kilogram racing car W 25, self-evidently with a streamlined body, and reported back to duty – opening the next, very successful chapter in the brand’s motorsports history.

The new racing formula brought to an end the juxtaposition of large, heavy and small, lightweight racing cars in the same category. In light of today’s racing formulae, which demand a minimum weight, a maximum weight limitation might appear strange, but with the 750 kilogram formula, the AIACR was aiming to restrict the speed of racing cars compared with the models of the previous generation. The assumption was that a light vehicle would necessarily be fitted with a smaller engine with a low output. In this process, they underestimated technological advances: in the era of the 750-kilogram formula between 1934 and 1937 alone, the engine output of Mercedes-Benz racing cars almost doubled.