Auto Union Type A was the first of the famous Auto Union racing cars from the 1930s. At the time German racing cars were given a silver paint finish, and therefore these cars were also called Silver Arrow.
After the successful W 25 Grand Prix racing car, Mercedes-Benz developed a new car for the 1937 season. The new W 125 racing car had an extremely sturdy, tubular oval frame made from special steel, with four cross members. It benefited from tests with production car frames as, for instance, the one used on the 1938 generation of the Mercedes-Benz 230. The wheels were located differently, by double wishbones and coil springs at the front, as on the celebrated, noble 500 K and 540 K models, and by a double-joint De Dion rear axle which ensured constant camber, plus longitudinally installed torsion bar springs and lever-type shock absorbers. Lateral links transferred thrust and brake moments to the chassis.
A new age for Mercedes-Benz motorsport dawned from 1934. The project for the future was the W 25. As to its premiere, Daimler-Benz set its sights on the Avus and Eifel races in the run-up to the French Grand Prix on July 1, 1934, the second of the season. To win the race in France would have been quite a feat, almost exactly 20 years after the one-two-three triumph of Daimler-Motoren-Gesellschaft (DMG) in Lyon. Eventually, it was an Alfa Romeo P3 Tipo B that actually won the race in Montlhéry, but it was the W 25 which represented the state of the art.