Seen as a successor for the six cylinder Adler Diplomat, it was an executive sedan/saloon featuring a strikingly streamlined body designed by Karl Jenschke (1899–1969) who till 1935 had been the Director of Engineering with Steyr-Daimler-Puch.

The Adler 2.5-litre was powered by a longitudinally installed water-cooled straight-six side-valve engine of 2,494 cc displacement, with a four-bearing crankshaft and pressured lubrication.

The radiator, engine and gear box were all set well forward in the car, and power was delivered to the rear wheels via a four-speed manual transmission which included synchromesh on the top three ratios.

The steering used a ZF manufactured Ross system Welded to the frame was a four-door fast back steel body for which the drag coefficient quoted was a remarkable 0.36.

[3] At the front two headlights were placed close together either side of the grill, but these proved inadequate, and in 1938 a second pair of “wide beam” lights was set into the wings, although from 1938 the regulations permitted only one of these.

[3] The Sport model shared its 2,494 cc 6-cylinder engine with the sedan/saloon, but in place of the standard car’s single carburetter this one came with three.

[2][3] The first “Autobahn Adlers“ were delivered to customers in November 1937, priced at 5,750 Marks for the standard bodied limousine.

Even in that context, however, the volumes achieved by the Adler 2.5-litre were less impressive than the car’s reception at the 1937 motor show might have led the manufacturer to anticipate.