On 23 November 1952 Mercedes-Benz celebrated a historic motor sports success: a double victory by two 300 SL sports cars in the legendary Carrera Panamericana road race covering more than 3100 km right across Mexico, from the border with Guatemala in the south to Ciudad Juarez on the northern border with the USA.

Great altitudes, thousands of bends and scorching heat were just some of the challenges facing the contestants. The team consisting of driver Karl Kling and co-driver Hans Klenk set up a sensational race record:

18 hours, 51 minutes and 19 seconds of driving time meant an average speed of 165 km/h on risky, basically public roads with no significant safety precautions. The runners-up, the SL team of Hermann Lang and Erwin Grupp, reached the finishing line 35 minutes after the winners. To commemorate that spectacular contest, “La Carrera Panamericana” has been held as a road race with historic cars once each year since 1988. This year’s revival will take place from 22 to 28 October 2010.

A succession of incidents during the Mexican road race held in 1952, such as the winning car’s collision with a vulture as well as countless tyre punctures on the rough asphalt, made that year’s Carrera Panamericana an unforgettable motor sports event. With a length of 3113 at the time, the gruelling route required a logistical marathon of servicing and tyre-changing points. In just four days, and in 8000 to 10,000-kilometre long stages, the “Carrera” took the contestants from Tuxtla Gutiérrez in the tropical south along the edges of deep crevasses and high passes to Ciudad Juarez in the north of Mexico. The drivers and cars had to endure burning-hot sunshine, temperature differences of between 5 and 40 degrees Celsius in the shade, different altitudes from sea-level to 3300 metres, the extremely punishing nature of the route and countless breakdowns, but nonetheless achieved average speeds that are still regarded as “fabulous” 50 years later.

SL: two letters become an automotive legend
The scene for the grandiose Mercedes success in this road race was set by the summer 1951 decision of the Daimler-Benz Executive Board to give the go-ahead for the production of a new racing sports car. The first example of the new car was ready by 13 March 1952, only nine months after this seminal executive decision. Its first outing was at the Italian “Mille Miglia” road race, where the new Mercedes sports car crossed the finishing line in second place.

Only rarely has a sequence of letters like the model designation SL – which was really only intended as an abbreviation for “sporty” and “light” – achieved the same charismatic status. These two letters are still the hallmarks of an unrivalled Mercedes tradition to this day – a living legend. The 300 SL achieved its sporting goals with flying colours. Although only the W 186 Saloon, the famous Mercedes-Benz 300, was available as a technical basis for time and cost reasons, the sports car was a success right from the start. Development chief Rudolf Uhlenhaut, who had given the decisive impulses for the 300 SL, later recalled: “We took the standard engine of the 300 and built a spaceframe and aluminium body around it.”

It was a winning combination, as numerous spectacular victories soon showed: after the Mille Miglia, the Mercedes sports cars caused a sensation on the Bremgarten circuit at the 1952 Berne Grand Prix, taking the first three places. In June 1952 Lang/Rieß and Helfrich/Niedermayr achieved another spectacular double victory in Le Mans, and in August of the same year the 300 SLs took the first four places on the Nürburgring. These motor racing victories motivated the Stuttgart company to look further afield for further, more exotic opportunities – also overseas, in the Carrera Panamericana.

Carrera Panamericana: the evocative name of a legendary road race
The construction project of the century was now completed, but hardly anybody noticed. In 1950 the newly prosperous Mexico was the first Latin-American country to complete its section of the Pan-American Highway, the monumental road crossing both North and South America, and therefore the first direct land link between Alaska and Tierra del Fuego. But this fascinating fact in itself was not enough to attract the world’s attention to Mexico and the nation’s proud achievement. What was to be done?

The solution was literally to be found in the road itself, as the Mexican Ministry of Transport was the first to realise: the head of the ministry at the time was immediately able to obtain the enthusiastic support of the Mexican President, Miguel Alemán, when he presented the idea of organising an international road race. The President reasoned that the “Carrera Panamericana” would draw the eyes of the world towards Mexico, and he was proved right.

“La Carrera Panamericana” – this exotic and highly evocative synonym for adventure and thrills not only captured the attention of confirmed motor sports enthusiasts. The race immediately became extremely popular in America, and it also gave rise to unexpected euphoria in Europe. And no wonder, as it attracted practically everyone who was anyone in the motor racing world. This applied to both the drivers – from Juan Manuel Fangio, Karl Kling, Hermann Lang and Alberto Ascari to Giovanni Bracco – and the manufacturers: the Europeans dispatched racing teams from Ferrari, Jaguar, Alfa Romeo, Lancia, Maserati, Gordini and Porsche. The USA was represented by the world’s largest manufacturers, Chrysler, Ford and General Motors, who were no less prominent with their Buick, Cadillac and Oldsmobile brands.

Although the time for a commitment by Mercedes-Benz could not have been more favourable, one of those on whom most of the responsibility fell was initially sceptical: racing manager Alfred Neubauer. Highly experienced in the motor racing world, he remembered that the rulebook for the first race in 1950 had only permitted cars that were produced in large numbers, and had at least five seats. As a result of this requirement, which was unusual from a European point of view and probably took the vehicles available in the nearby USA heavily into account, large, heavy cars took part which were not really suitable for an extremely fast road race with numerous bends. The first winner was the American Hershel McGriff in an Oldsmobile 88. His time was more than 27 hours, around eight hours more than that taken by Kling and Klenk in the 300 SL just two years later.

Executive Board decision: Mercedes-Benz at the starting line for the 3rd Carrera Panamericana
The organisers relaxed the rules for the following year, 1951, and in 1952 the rulebook finally allowed cars that had been specially prepared for the rough conditions of a road race. The newly designed Mercedes-Benz 300 SL seemed predestined for the Carrera: with a kerb weight of only 870 kilograms, a wheelbase of 2.40 Metern, what were then considered highly effective drum brakes, an engine output of 180 hp, a small frontal area and the then sensationally low Cd-figure of 0.25, plus a top speed of 240 km/h, it was the right sports car in the right place at the right time.

Neubauer overcame his reservations and began to smell success in Mexico, no doubt encouraged by the remarkable victories in Europe. Executive Board resolution No. 4150 of 22 September 1952 duly confirmed that Mercedes-Benz would enter three cars in the third Carrera Panamericana to be held from 19 to 23 November of that year.

Preparations: altitude tests in the Alps and a sea voyage to Mexico
As the time remaining for the preparations necessary for a road race of this extreme nature was decidedly short, racing driver Karl Kling hurried off to the Alps just one day after the Executive Board’s decision, in order to conduct altitude tests during which the ignition timing and the carburetor nozzles of the 300 SL would be adjusted to the extreme Mexican altitudes of up to 3300 metres, more than 800 metres higher than any European mountain pass.

In order to be on the spot as early as possible, the vehicles and the service team embarked on the “MS Anita” in Hamburg in early October 1952 for a voyage lasting several weeks to the Mexican port of Veracruz. At the end of the month they were followed by Alfred Neubauer with the driver teams of Karl Kling/Hans Klenk and Hermann Lang/Erwin Grupp, onboard a KLM DC 6 starting in Stuttgart-Echterdingen and flying via Amsterdam, Gander, Montreal and Monterey – at the time an exhausting ordeal lasting 2 days.

In Mexico they were already awaited by the man designated to drive the third 300 SL, the young American racing driver John Fitch. Some time later he described his euphoria after making his first contact with the 300 SL, which was a Roadster rather than a Coupé as driven by Kling and Lang, as follows: “What a racing car! The unmistakable smell of particularly hard brake linings mixed with a touch of hot oil hung around the cockpit. The gas and brake pedals were ideally positioned in relation to each other, so that it was possible to pivot your right foot over to the gas pedal while braking. The transmission was a delight – gearshifts were extraordinarily smooth and precise.”

Great haste and concentrated preparations were necessary after their arrival. Only three weeks remained to the three dozen Mercedes motor sports specialists, drivers, helpers and mechanics charged with preparing everything for this extremely long and arduous road race in the most difficult geographical and climatic conditions. During this time they were able to make the 300 SLs fit for the extreme challenges. The teams also did their best to record and remember features of the 3100-kilometre long route, with its countless bends, narrow bridges and other potential dangers which were usually hard to recognise in advance at high speeds. A single test drive over the enormous distance, which was carried out at a much slower speed in a borrowed Mercedes 300 Saloon, meant that only patchy results were achieved. But the biggest cause for concern was the decidedly rough asphalt, which literally shaved the treads off the tyres at a fantastic rate during the thousands of cornering manoeuvres.

Ready for the off: 90 cars at the starting line in Tuxtla Gutiérrez
On Wednesday, 19 November 1952 the race finally started, when 90 cars (29 sports cars and 61 touring cars) set off from Tuxtla Gutiérrez in one-minute intervals from 6.30 a.m. onwards. The well-organised teams of supporting personnel for the road race included a monumental 40,000 soldiers, 3000 medical people and 600 officials. 65 aircraft transported personnel and materials from stage to stage.

Collision: shattered windscreen, unconscious co-driver
As the exploratory test drives had already indicated, the race was very hard on both men and materials. Fate already struck a blow for Kling and Klenk during the first stage. Kling was roaring towards a long right-hand bend at 200 kilometres per hour, and noticed the vultures squatting at the roadside too late. One of them lifted off and flew straight into the windscreen of the 300 SL. Co-driver Hans Klenk was struck in the face and lost consciousness for a while, but he overcame the shock like a true professional: when Klenk came round after his brief spell of unconsciousness, he shouted: “Karle, keep going!”. So Karl Kling continued at full throttle. Around 70 kilometres further on, when stopping for a wheel-change, Klenk washed his face while helpers gathered glass splinters and the remains of the vulture from the car’s interior, and off they went again towards Oaxaca, the destination for that stage. On arrival Hans Klenk was given a brief medical examination and pronounced healthy with a cheery “vaya con Dios”. To protect themselves from any further collisions of this kind, Kling and Klenk bolted eight vertical steel rods in front of the new windscreen while discussing the zoological category of the dead bird. They finally agreed that its wing-span was around 115 centimetres, and that it weighed the equivalent of five fattened geese. With hindsight, it was this incident, which actually encouraged the two drivers all the more, that made the final victory and the Carrera Panamericana such a popular legend.

The prayer-book: premiered at the Carrera Panamericana
The Mercedes teams continued to roar across Mexico in their 300 SLs: Karl Kling and Hans Klenk, Hermann Lang and Erwin Grupp, John Fitch and Eugen Geiger. The mountain stretches included some of the world’s most dangerous roads. With deceptively steep gradients, sudden changes in direction and wicked hairpin bends, they made extreme demands on the brakes, suspension and tyres while requiring the utmost courage and concentration on the part of the drivers. There were yawning crevasses and sheer drops of up to 300 metres on both sides of the road.

Being over-cautious slows you down, however. So the 300 SL drivers improvised in their own way: Hans Klenk had made notes on major danger spots and their distances during the exploratory trips. Kling was initially unconvinced that this laborious scribbling would do any good, but after a few tests he was forced to admit that “it seems to have its merits after all”. Their success confirmed this, and Hans Klenk is rightly seen as the inventor of the so-called “prayer-book” which continues to be an indispensable aid in any rally. In addition to his great instinct for covering unfamiliar routes at high speed “by sight”, Karl Kling was therefore also able to rely on these recorded notes. The murderous route took its toll on both men and materials, and they carried out many a minor repair as they struggled from stage to stage. The unsung heroes were the mechanics. At the end of every stage they rushed to change gear ratios and replace windows, tyres, clutches, shock absorbers, doors and often also the sweat-soaked shirts of the drivers.

Karl Kling and Hans Klenk were in fourth place when the final day of the Carrera Panamericana dawned. Kling und Klenk then proceeded to “fly” through the final stage in a fabulous time, winning a comfortable victory to the cheers of thousands of enthusiastic spectators from Mexico and Texas. Karl Kling: “On some stretches we drove so fast that racing manager Alfred Neubauer in his chartered DC 3 was unable to keep up.” The victorious cars showed countless signs of their ordeal: the wind and sand had sandblasted the aluminium bodywork, which was also severely scratched, dented and distorted by flying stones.

Even the disqualification of their team colleague John Fitch only marred the pleasure of the record-breaking double victory by Karl Kling und Hans Klenk very briefly. John Fitch was disqualified after much chaotic to’ing and fro’ing, having clocked the best time on the final stage. After starting off for the previous stage, he had returned to the starting line to have the track of his car adjusted, and apparently used third-party assistance.

This triumph in the 1952 Carrera Panamericana road race, a historic event in the world of motor sports, gave an enormous boost to the popularity of both the drivers and Mercedes-Benz. Racing manager Alfred Neubauer commented that the success of the Stuttgart-based car brand was “the result of combined driving skill, precise preparations and top-class technology”.

The double victory not only marked the highlight of a racing season that had already been highly successful for Mercedes-Benz, as it also impressively demonstrated the capabilities of the regenerated German car industry while ensuring further development work on the now world-famous Mercedes-Benz 300 SL. The prototypes of the sports car used for the Carrera Panamericana are rightly seen as the progenitors of this legendary model series, which celebrated its world premiere at the International Motor Sports Show in New York shortly afterwards, on 6 February 1954. Mercedes development chief Rudolf Uhlenhaut left no doubt about the idea behind the new model when it was presented: “You would be right to think of the SL models as sports cars – with the emphasis on sport.” The message remained unforgotten: more than four decades later the gullwing was voted “Sports Car of the Century”.

Source: Daimler AG