Road cyclist Karl-Dietrich Diers was a member of the East German 100 km time trial team that finished a disappointing 10th at the 1976 Montréal Olympics. In the individual road race, he placed 16th. He helped his club ASK Frankfurt on Oder win the East German 100 km team trial title in 1973, 1974, and 1977. In 1974 and 1977 he also ascended the podium in the road race, placing third on both occasions. In 1974 Diers won a bronze medal at the Worlds in the 100 km team trial race. He trained as a watchmaker but later worked as a cycling coach.