As an amateur, Karstens participated in both speed skating and cycling. His best performance on the ice was an eighth position in the 1963 Dutch Allround Championships. In cycling, he had several national wins, before racing to gold in the 100 km team time trial at the 1964 Tokyo Games. This performance helped secure Karstens a spot in the pro circuit the following year. As a sprinter, he immediately proved his capabilities, winning the “Sprinters’ Classic” Paris-Tours, placing second in the Giro di Lombardia and winning the 21st stage of the Tour de France. He went on to win stages in all Grand Tours, 1 in the Giro d’Italia, 6 more in the Tour and no less than 14 in the Vuelta a España. In both 1967 and 1973, Karstens won four stages in the Vuelta.
In two more classics, he crossed the line first: the 1969 Giro di Lombardia and 1974 Paris-Tours, but Karstens lost both wins. He failed a doping test in Lombardia, and supposedly “missed” the doping test in Tours. He also missed doping control after his stage win in the 1974 Tour, but was then reinstated, earning him the first of two days in the Yellow Jersey. In the peloton, where he raced until 1980, Karstens was known for his humor. On one occasion, he escaped from the pack, only to hide in the bushes and rejoin the pack from the back. He then enjoyed the peloton “chasing” him. Other such performances included grabbing a spectator’s bikini top and “blocking” the road with his bike.
Netherlands