Rudi Uhlenhaut — Mercedes' Driving Designer

July 4, 2022

Until recently, Rudolf Uhlenhaut's name wasn't familiar to most. Now, his surname has become synonymous with “the world’s most expensive car.” This got me curious about the man behind the name, so down the rabbit hole I went.

Rudi, as he was known, was a remarkable innovator who took a “systems-level” approach to race car design. Uhlenhaut was the great mind behind world-dominating cars like the 1937 W125, the Le Mans-winning W194, the record-setting 300 SLR, and the 300 SLGullwing.

Yet, he was so much more. He preferred to sit behind the wheel of his cars, not behind the drawing board. In fact, he was entered as a Mercedes back-up driver in the fateful 1955 Le Mans race. Uhlenhaut deserves a better fate than to simply have his name utilized as shorthand for the $142M coupe, considering that during his entire life he never once owned a vehicle!

By Way of Britain

Despite his ties to Mercedes and his Germanic name, he was actually a Brit by birth and citizenship. (Betcha didn’t see that one coming!) His father was a German national who was working in London, and Uhlenhaut’s mother was British, so he carried dual citizenship from his birth in 1906. 

Young Rudi lived his early years in Highgate, a suburb of London, until the Great War ultimately led the family to relocate to Bremen, via a stint in Brussels. In 1926 at age 20, he entered university in Munich where he studied engineering. At age 25, he started work at Mercedes-Benz designing road cars under Fritz Nallinger. 

As part of his job, he would often head to the Nurburgring to test passenger cars, which gave him firsthand experience in automotive dynamics and high-performance driving. Although he never formally raced, he had a natural talent for pushing a car to its limits on the track.

In five short years, Uhlenhaut was put in charge of Mercedes’ Rennabteilung (Racing Dept.) where he was able to directly apply his hard-earned experience. His role was extremely high profile, as the Nazi party put a premium on glorifying Germany’s technical prowess in the arena of motorsport. They pumped money into both Mercedes-Benz and Auto Union to finance their racing programs in Grand Prix and sports cars. Yet, Uhlenhaut was closely monitored by the Gestapo because of his British citizenship.

In 1936, the “other” German manufacturer Auto Union had ascended to the top rung, winning three of four events to dominate the European Championship. Uhlenhaut’s job was to reverse the fortunes of Mercedes-Benz, whose W25 had underperformed compared to the monstrous, mid-engined Auto Unions designed by Dr. Ferdinand Porsche.

Uhlenhaut testing the W154 at Monza, 1938.

The Racing Engineer

Upon taking the job, the racing team went to test the 1935 and 1936 Grand Prix cars at the Nurburgring in August 1936. After a couple of days, pro drivers Rudolf Caracciola and Manfred von Brauchitsch headed home. Uhlenhaut jumped in and drove the cars himself, despite never having driven a race car before! Famously, at one point during a high-speed test, a wheel came off and Uhlenhaut kept his foot in it. He reportedly did thousands of kilometers of testing around this time.

He came home with a long list of deficiencies that were revealed through his tests. His new design, the W125, would aim to correct all of them. Similar to Italy’s Vittorio Jano, Uhlenhaut focused on improving driving dynamics, by lowering the center of gravity and upgrading the suspension, rather than focusing on pure horsepower. 

The W125 featured Mercedes’ first alloy, tubular space frame. Utilizing ovalized tubing resulted in a much stiffer chassis than its predecessor. An early independent front suspension provided greater travel and softer springs for better road handling. 

1937 W125

While optimizing for driveability, nothing was held back with regard to the engine. The 5.6L supercharged inline 8-cylinder engine produced 645 hp, pushing the car beyond 300 kph. The W125 was considered the most powerful race car until the advent of the Can-Am series in the 1970s.

Uhlenhaut’s astute assessment of the W25, and his ability to overcome its deficiencies with the W125, proved successful, as Mercedes-Benz dominated the 1937 Grand Prix season. Hermann Lang drove it to victory in its maiden race, and the W125 won four of the five rounds of the European Grand Prix Championship. Quite a turnaround!

A pair of W194s at the 1952 Le Mans 24 Hours.

The Birth of the 300SL

Fast forward to post WWII once Germany was getting back on its feet. It was 1948, and Uhlenhaut was invited to return to Mercedes. In June 1951, the Mercedes board voted to return to Grand Prix racing in 1954, the year a new set of rules were to be implemented. Uhlenhaut was appointed to lead that effort.

Since he had some time, he worked on a new concept for a sports car. Thus, the W194 was born. He adapted the 3.0L inline-six engine from a W186 saloon car into a cutting-edge, tubular space-frame chassis -- and “gullwing” doors were included as a way to stiffen the chassis. 

The W194 was a sensation. It entered five races, and won four of them, one of which was taking the overall victory at the 1952 Le Mans 24 Hours! After some cajoling, Mercedes developed the 300SL (W198), which was introduced in 1954. The Gullwing was later named “the sports car of the century.” 

Uhlenhaut went on to develop many other dominant race cars, from the double World Championship-winning W196 F1 car, to the 300 SLR that won the 1955 Mille Miglia with Stirling Moss and Denis Jenkinson in a whisker over 10 hours. This car was later adapted into a road-going coupe of which only two were made. Rudi drove #0008/55 as his daily driver (read that again). This is the exact car that just sold for a princely sum. 

Uhlenhaut celebrating Moss's victory at Aintree in 1955.

Faster than Fangio

To conclude, let’s recount the story that encapsulates Uhlenhaut’s status as a true legend. In 1955, Fangio came around to test at the Nurburgring. El Maestro came back into the garage and complained that the car had not been well prepared for the test. 

Still wearing a suit and tie, Rudi Uhlenhaut hopped into the car and tore around the Ring -- besting Fangio’s time by three seconds. Upon returning, he suggested to the World Champion that all he needed was to practice a bit more.

Uhlenhaut was a beloved figure at Mercedes, even after his retirement in 1972. He died in May 1989 at age 83. If he were around today, I wonder what he would think of all this hullabaloo about his “company car.” I suspect he’d be just as happy if it was used to make a run to the grocers as he once did, rather than the spectacle it has now become.


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