It was on January 9 and 10, 1968, when Mercedes-Benz presented the completely newly developed upper mid-size sedans in Sindelfingen. They were divided into the W 115 (four and five-cylinder engines) and W 114 (six-cylinder engines) model series. The model series from the ancestor series of the E-Class impresses with a clear design language and a design that is independent of the luxury class. The success of the "Stroke Eight", as fans later call this generation of vehicles after the addition of "/8" to the model designation, is overwhelming: for the first time, more than one million units of a Mercedes-Benz vehicle family are sold. In addition to saloons, it also included coupés, long-wheelbase saloons and chassis for special bodies.
Stylistically and technically modern
The new vehicle family is assigned to the W 115 (four and five-cylinder engines) and W 114 (six-cylinder engines) series. Externally, the respective models are completely identical in terms of their dimensions. They can only be distinguished by equipment details as well as radiator grille and bumper variants. The 200 D and 220 D diesel engine models and the 200, 220, 230 and 250 petrol engine models are available at market launch. The range was subsequently expanded further.
The stylistically and technically very modern vehicles represented a small revolution. However, the new upper mid-range had nothing in common with the wild student protests of 1968. Instead, Mercedes-Benz successfully sharpened the profile of this market segment - the future E-Class - with the "Stroke Eight". This development carried particular weight because the Stuttgart brand added coupés (market launch in November 1968) and long-wheelbase saloons (market launch in December 1968) to the model series family in the same year. Mercedes-Benz thus now offered a comprehensive portfolio of different body styles and engines in the independent upper mid-size class.
"Well-calculated perfection"
Even at first glance, the "Stroke Eight" impresses with its clear and harmonious design, created by Paul Bracq in the stylistics department headed by Friedrich Geiger. In addition, there are technical innovations such as the rear diagonal swing axle. With this, the engineers achieve the goal of combining the driving comfort typical of the brand with further improved driving characteristics.
This is what the trade magazine " auto motor und sport" wrote in issue 4/1968 about the 200 (W 115) and 250 (W 114) models: "The wet and icy Hockenheimring confirmed the experience gained on the Targa Florio circuit: Driving stability has been significantly improved with the new axle." The overall impression of the "Stroke Eight" is summed up in the headline of the article: "Well-calculated perfection" is the title of the new upper mid-range model from Mercedes-Benz.
Seven-year development phase
The development of the new generation of vehicles began in 1961, with Prof. Dr. Fritz Nallinger, then Board Member for Development at Daimler-Benz AG, advocating from the outset that the new model should be more clearly differentiated from the luxury class vehicles. This meant the definitive end of the standardized body, as implemented in the "Ponton" and "Heckflosse" sedans. The specifications envisaged a more compact vehicle than the W 110, but with the same amount of interior space. In addition, new chassis designs were to further improve the driving characteristics. A decision is made early on to extend the drive range to include six-cylinder engines.
The result is a saloon with harmonious proportions, whose wheelbase increases by 50 millimetres to 2,750 millimetres compared to its predecessor, while the overall length is reduced by 55 millimetres to 4,680 millimetres. In addition, the saloons are 25 millimetres narrower and 55 millimetres lower than the small "tail fins". Mercedes-Benz is testing the developments in passive safety with 26 accident tests, among other things. The crash tests show that the "Stroke Eight" not only meets the US standards for a collision at 30 miles per hour with 100 percent overlap, but far exceeds them.
The chassis has also been significantly enhanced compared to the W 110. The two bogies are connected to the body via soft rubber mounts. At the front axle, double wishbones with interlocking pivot axles reduce front end dive under hard braking. At the rear, the newly designed "diagonal swing axle" is used, a semi-trailing arm rear axle. It reduces toe and camber changes in bends as well as during compression and rebound. For the first time in the Mercedes-Benz upper mid-size class, all four wheels are fitted with disc brakes. Power steering and hydraulic level control are optional.
Successful model in E-Class history
In the classic car scene, the upper mid-range Mercedes-Benz vehicles built from 1968 to 1976 are known as the "Stroke Eight". However, this name for the model series does not originate from the brand itself. Rather, it only emerged from the linguistic usage of the fans some time after the premiere in January 1968 - derived from the abbreviation "/8", which identifies the 1968 models in the model range.
The abbreviation "Stroke Eight" subsequently became the catchy name for all variants of this upper mid-range model. This also included the top-of-the-range 280 and 280 E (1972) as well as the 240 D 3.0, the world's first five-cylinder passenger car, which appeared after the model update in 1973.
After the premiere of the four-door saloon in January 1968, the market launch is not long in coming. The four-door saloon with six windows and a 650 millimetre longer wheelbase was built from March 1968. In contrast to the standard saloons, Mercedes-Benz equipped this long-wheelbase version with larger 15-inch wheels and a correspondingly adapted shorter rear axle ratio due to the changed angle of bank. The two-door coupé was finally built from October 1968. The sporty and elegant two-door model has the same wheelbase as the saloons, but is 45 millimetres lower. The vacuum-locked backrests of the front seats are automatically unlocked when the doors are open, allowing easy access to the rear bench seat. In contrast to the saloon, the rear bumper is pulled forward to the rear wheel cut-outs.
The "Stroke Eight" proves to be an absolute success: for the first time, Mercedes-Benz builds more than one million saloons in a model series family - 1.8 million in total. And more than 1.9 million units of all body variants combined were sold. It is fitting that the two millionth Mercedes-Benz passenger car produced since 1946 is also a "Stroke Eight". The 220 D saloon rolled off the production line at the Sindelfingen plant on May 9, 1968. The last "Stroke Eight" vehicles were built in 1976 - at a time when production of the successor series W 123 had already started.
