Fahrrad-Speck was a bicycle shop based at Arndtstrasse 23, Schwenningen in South West Germany (West Germany at the time).
Fahrrad-Speck was the exclusive agent for Bauer bicycles in Schwenningen. And Schwenningen was the home town of Heinz Müller, the 1952 World Road Race Champion, who rode for the Bauer professional cycling team.
Today an engineering company called Robert Speck GmbH is based at Arndtstrasse 23, Schwenningen, and claims that it was established in 1942. Heinz Müller was, himself, an engineer and Frank Berto claims that he did development work on the Altenburger range of derailleurs. Perhaps some of this work was in association with Herr Speck.