Udo Hempel was a member of the West German pursuit team at the 1968 Mexico Olympics that reached the final against Denmark. The Germans always led and the race looked over when, after 9 of 12 laps, a Danish rider went off the back. However, they re-grouped but still trailed at the bell. The German team then began to split, with Jürgen Kissner dropping off the pace. As his teammate Karl Heinz Henrichs passed him, Kissner’s hand appeared to touch him, possibly giving him a slight push. Germany held on to win by 3½ seconds, but Kissner was an East German defector and East Germany immediately protested that the touch had been an illegal shove. After a 15-minute conference among the judges, West Germany was disqualified, and Italy and the Soviet Union were announced as the silver and bronze medal winners. FRG officials then protested, stating that Italy and the Soviets should not be placed ahead of their riders. Another long conference ensued, and the result was announced as Denmark first and Italy third. No silver medal placement was given until a meeting of the Fédération Internationale Amateur de Cyclisme (FIAC, later the UCI) in November, when West Germany was awarded second place and their silver medals.
In 1972, Hempel and the West German pursuit team won the gold medal at the München Games. In 1970, he also won a World Championship pursuit gold. Hempel also won eight West German national titles. He was appointed the national chief coach from 1982-88, and later organized cycling events in Germany.