The 1937 Mercedes-Benz W125 Rekordwagen is an iconic machine, a testament to German engineering prowess and a symbol of the relentless pursuit of speed. This museum-worthy vehicle, a variant of the formidable Mercedes-Benz W125 Grand Prix car, was specifically engineered for one purpose: to break land speed records. While the original bodywork remains safely housed in a museum, a replica body is used when the car is showcased at events, preserving the irreplaceable original.
To achieve record-breaking velocity, aerodynamic efficiency was paramount. Wind tunnel tests conducted decades later revealed the W125 Rekordwagen’s body boasted an incredibly low drag coefficient of just 0.170. This sleek, streamlined design was the result of close collaboration with aircraft manufacturers, pushing the boundaries of aerodynamic understanding at the time. The focus on minimizing air resistance is evident in every curve and panel of its bodywork.
Powering this aerodynamic marvel was a colossal 5.576-liter Daimler-Benz V12 DAB engine, supercharged to produce a staggering 765 horsepower (563 kilowatts) in 1938 specification. Interestingly, for the record attempt, engineers further tweaked the engine, adding extra carburetors to unleash an additional 29 horsepower (21 kW) over the standard DAB engine configuration used just weeks prior. This relentless optimization also included improvements to engine reliability and fine-tuning the fuel-air mixture delivery to each of the twelve cylinders. An innovative ice-cooling system was implemented, packing the radiator in a container with 5 kilograms (11 pounds) of ice and 48 liters (12.6 gallons) of water to manage the extreme heat generated by the powerful engine.
The Mercedes-Benz W125 Rekordwagen etched its name into history on January 28, 1938. Driven by the legendary Rudolf Caracciola on the Reichautobahn, it achieved a speed of 432.7 km/h (268.9 mph) over a flying kilometer and 432.4 km/h (268.7 mph) over a flying mile. This remarkable feat stood as the fastest speed ever recorded on a public road for nearly 80 years. Caracciola’s record remained unchallenged until November 2017, when Koenigsegg surpassed it with the Agera RS, achieving 277.87 mph. The Mercedes-Benz W125 Rekordwagen remains a symbol of automotive speed and a highlight of Mercedes-Benz’s rich racing heritage.
