What is so special about the Mercedes Benz W 196?

The Mercedes Benz W 196 or 300 SLR is amongst one of the most famous, if not the most beautiful racing cars of all time.  Other than that, what is so special about the Mercedes Benz W 196?

When it comes to German motorsports, most people think of Porsche with its 906, 917, 935, 956, and 962. However, the truth is that the Silver Arrow across town, Mercedes-Benz, also has a vibrant motorsports history.  At the top are the Silver Arrows of the mid-1950s, the Mercedes-Benz W 196.

The Mercedes-Benz W 196 R was designed for the 1954 season.  It met all of the new Grand Prix formula requirements established by the sport’s governing body, the CSI (Commission Sportive Internationale).  The engine capacity of 750 ccs with or without a supercharger could have a free choice of a gas mixture and covered a racing distance of 300 kilometers or three hours.

MB W154 racer

Two types of the Mercedes-Benz W 196 R: the monoposto and streamliner.

Two body styles of the W 196 R were produced.  In its inaugural race at Reims, the track was very fast.  Since the event was a high-speed race, a streamlined version of the SLR was finished first. A variation having open wheels was also produced.

The two variants of the W 196 R were designed with interchangeable bodies. Thus, a chassis could be wearing a streamliner body one race and monoposto body the next.  Which body a chassis wore was determined by the circuit’s characteristics, the racing strategy, and each driver’s preferences.

Historic Mercedes Benz SLR

History of the development of the Mercedes Benz W 196 R

Fritz Nallinger entirely oversaw the W 196 R project.  Assisted by Rudolf Uhlenhaut, Chief Engineer of the Racing Department, who later headed the Car Testing Department, had a crucial impact on the development. Uhlenhaut was in charge of a team of engineers that included Hans Scherenberg, Ludwig Kraus, Manfred Lorscheidt, Hans Gassmann, and Karl-Heinz Göschel, as well as other corporate executives. Even while the whole was far more than the sum of its parts in the case of the W 196 R, the vehicle was cutting-edge at the time.

In the two years that followed, 14 vehicles and a prototype were produced. Its initial streamlined body was both practical and attractive. However, starting with the German Grand Prix at the Nürburgring in early August 1954, an open-wheel (monoposto) version was included in the lineup. Its tubular space frame was light and robust. Its suspension was revolutionary at the time, consisting of torsion bars and a revolutionary single-joint swing axle in the back.

1955 Mercedes Benz SLR

What was the engine driving the Mercedes Benz 300 SLR (W 196 S)?

Whereas the Mercedes-Benz 300SL was powered by a 3-liter six-cylinder engine, the 300 SLR featured a 2.5-liter inline eight-cylinder engine with direct injection and desmodromic valve management mounted into the space frame at a 53-degree angle on the right side of the car.  This was done to lower the center of gravity and reduce the frontal area.  Performance was impressive, putting out 256 horsepower at 8260 rpm.  In 1955, output was increased to 290 hp at 8500 rpm.

For the 1955 season, racing manager Alfred Neubauer made a historic decision. He hired Juan Manuel Fangio and the up-and-coming Stirling Moss to form an almost unbeatable duo.

MB W154 racing engine

Who were Juan Manuel Fangio and Sir Stirling Moss?

Juan Manuel Fangio was an Argentinian race car driver who dominated the first decade of Formula One racing, winning the World Drivers’ Championship five times during the 1950s – a record that stood until beaten by Michael Schumacher.  His championship wins were with four different teams: Alfa Romeo, Ferrari, Mercedes Benz, and Maserati, a record that stands to this day.  Fangio also holds the highest winning percentage in Formula One – 46.15% – or, winning 24 of the 52 Formula One races he entered.

Like Fangio, Sir Stirling Moss was another legendary driver whose most famous drive was the 1955 Mille Miglia.  Driving a 1955 Mercedes-Benz SLR (#722), Moss with navigator Denis Jenkinson completed the 1,000-mile auto race held on a course made up entirely of public roads on April 30 and May 1, 1955.  Sterling, with Jenkinson by his side, completed the 992-mile journey in 10 hours, 7 minutes, and 48 seconds at an average speed of 99 miles per hour.  This is an average speed over almost 11 hours on public roads around Italy in 1955!  The second-place finisher, Juan Manuel Fangio crossed the line alone, 32 seconds later in a second 1955 Mercedes-Benz 300 SLR.

Sterling Moss winning race

A case study in weight optimization

To balance the weight of the SLR, heavier parts were placed towards the very front or very back of the vehicle.  For example, the water and oil coolers were in the front, and the fuel and oil tanks were in the rear.  The idea of weight savings extended to the wheels as well.  To minimize the rotational mass of the wheels, the duplex brakes were centrally mounted in front of the engine and were excellent. Lightened wheels and a small rotational mass enables faster acceleration and less time to stop, translating into better performance.

engine compartment of the MB 300SLR

Brilliant engineering

Before a single eight-cylinder racing engine was produced, extensive testing was performed on a single-cylinder test unit having a capacity of 310 ccs and four valves.  Testing uncovered a flaw that had plagued the Silver Arrows going back to the 1930s: weak valve springs created valve gear issues above 8,000 rpm.  Engineer Hans Gassmann, came up with a solution while returning home from work.

The opening and closing of the valves would be controlled by cam lobes and rocker arms, eliminating the need for springs. His approach enabled the engine to rev higher safely, producing more power.    In the end, the engineers opted to run two valves per cylinder because it allowed them to use larger, heavier valves.

Historic Mercedes Benz SLR race car 01

What is the racing record of the Mercedes Benz W 196?

The track record of the W 196 was impressive.  It had nine victories, recorded fastest laps, and eight pole positions in the twelve Grand Prix races in which it competed.  It was also the vehicle in which Juan Manuel Fangio drove to world champion victories in both 1954 and 1955. After a very successful run, there was very little room left for growth. It was effective and certainly amongst the most beautiful racing cars in history.

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