Adler (German for eagle) is yet another of the German marques that produced both Cars and Motorcycles with a proud history on both fronts. The company was founded in 1886 by Heinrich Kleyer, and like many others was a producer of bicycles. This was supplemented in 1896 by producing typewriters, which turned out to be a good choice for diversification. Their first motorcycle was produced in 1899 and used a De Dion engine, and then they developed their own engine just after the turn of the century. The early years of Adler were dominated by the car division where they were renown for their coachwork. They also concentrated on smaller lighter vehicles. Popularity reached a peak in 1929 when Clarenore Stinnes (already a well known racing driver) completed a trip around the world in her Adler Standard 6.
With the economic collapse in the early 1930s, light cheap motorcycles regained some emphasis from the cars, and a number of models all under 250cc were produced. In particular, Adler reverted to putting a small engine (in this case a Sachs 98cc) into a frame combined with a number of bicycle parts. Small cars were also produced until the beginning of the war. After the war, Adler looked at the market, and decided not to resume the production of automobiles. This was arguably their critical error. They felt that the market would be flooded by cheap cars from everywhere (particularly America). They decided instead to concentrate on motorcycles, and produced small two-stroke machines up to the limit allowed by the Allied restrictions.
Soon 60cc motorcycles became 100cc, and Adler enjoyed good sales results. As capacity increased, the M200 of 1951 was praised by the press, but it was quickly joined by the M250 in order to match the competition from Horex and NSU. Unlike others, Adler concentrated on 250cc and below. In this era, Adler really enhanced the small capacity market, and entered the scooter and moped markets as well. They took the RS 250 racing in 1954, and in 1955 converted to a water-cooled version. They enjoyed some success with privateers in endurance events, but could not mount a good factory effort due to rapidly declining finances.
In 1954 their motorcycles received a new front fork which depleted R&D funding and left them with a plunger rear end when everyone else was introducing a swingarm. In the big decline of the motorcycle market in the mid 1950s, Adler found themselves in the same boat as BMW, DKW, etc. However, with no car division to help sustain them, and only bicycles to fall back on, they were in worse shape. They absorbed TWN in 1956 in an effort to keep motorcycles afloat, but ultimately closed the doors in 1957. With clubs in England, the Netherlands, Australia, and elsewhere, despite the doors closing some 50+ years ago, the eagle still flies.