Testing of the new C-Class began in (Northern) summer 2003. A total of 280 prototypes completed systematic non-stop tests under various climatic and topographic conditions. These included the "Heide" endurance test, one of the world's toughest test programmes for newly developed cars. This torture-track test, carried out over a period of four to six weeks, goes back more than 50 years to a time when Mercedes performed much of its test driving on Lüneburg Heath ("Heide" is the German word for "Heath”). It is equivalent to 300,000 kilometres of everyday driving by a Mercedes customer.

Mercedes-Benz replicated these pothole and cobblestone-covered routes at its facilities in Stuttgart and Sindelfingen and now uses the data gathered during these in-house tests to control test rigs. This means the highly sophisticated rigs can relentlessly shake and bend car bodies around the clock to reproduce the driving conditions experienced during the "Heide" torture-track endurance test. The forces acting on the connecting points between the chassis and body are immense – up to 20,000 Newtons – and they occur in quick succession. This is equivalent to a weight of up to two tonnes.

Durability testing: one of the world's toughest test programmes

The computer data compiled during the "Heide" torture-track endurance test are also used for chassis durability testing. Complete front and rear axles go through this unique series of tests around the clock on six servo-hydraulic test rigs. Mercedes engineers use four further installations to test the wheels, wheel bearings and wheel hubs for 60 hours non-stop on a simulated Hockenheimring Grand Prix circuit, during which time the chassis components are subjected to colossal lateral forces that stretch them to breaking point.

Similarly, the axle joints and bearings have to withstand extreme loads before they get the go-ahead for series production and installation in the new C-Class or other Mercedes models. In addition to permanent pressure and movement tests with forces of up to 35,000 Newtons, axle components must also resist extremely high temperatures of 90 degrees Celsius – verified in axle-joint field tests in city traffic in Tokyo.

Mercedes passenger cars also have to endure other simulated everyday conditions during testing, such as a high-pressure water jet (80 bar) and the systematic spraying of the joints with ice-cold dirty water and fine, hot sand dust over a period of three weeks. The most extensive test cycle in this environmental simulation lasts three weeks and includes over one million axle-joint load cycles – far more than any Mercedes-Benz usually experiences during its long lifetime.

The Mercedes-Benz Technology Centre has a total of around 160 innovative test rigs for chassis component durability testing alone.

"World Test" on three continents

Following a series of systematic long-distance tests in everyday traffic and at proving grounds, during which the cars were subjected to such high loads and stresses that they aged at a vastly accelerated rate, the 18-week "World Test" was one of the highlights of the systematic test marathon for the new C-Class. Four fully equipped pre-production vehicles successfully came through the tests in Germany, Finland, Dubai and Namibia. Here, under widely fluctuating climatic and topographic conditions, all of the vehicle components and systems – from the diesel particulate filter to the seats, from the door hinges to the shock absorbers – were tested once again.

Furthermore, 15 new C-Class pre-production models took part in a stiff final examination before production launch, involving tests in six countries within a period of seven months. Never before has a newly developed Mercedes model undergone such an extensive additional test programme – and passed with such flying colours.