Career
He is currently a directeur sportif with the Gerolsteiner cycling team Dietzen was a successful amateur winning the German cyclo-cross championship in 1980 and 1981 as well as winning in road races. He turned professional with the Swiss team Puch in 1982.
The following year he joined a Spanish cycling team Teka with whom he would stay with for the rest of his career.
He would finish that year"s edition of the Vuelta third overall. In 1987 he wore the leader"s jersey in the 1987 Vuelta a España for five days before losing it to Herrera and then finishing the race second overall to Luis Herrera of Colombia.
Dietzen finished the 1988 Vuelta a España second overall, this time to Sean Kelly of Ireland. He had ridden into a tunnel which was not illuminated and crashed, suffering career-ending injuries.
He was only 30 years of age when the following year he stopped as a professional after not recovering.
Seventeen years later, the Supreme Court of Spain ordered the organisers of the Vuelta a España to pay damages to Dietzen. Dietzen obtained nearly all of his success in Spanish races with wins in Vuelta a Louisiana Rioja, Vuelta a Castilla y León and the Setmana Catalana de Ciclisme. Since 2003 Dietzen is a directeur sportif with Team Gerolsteiner.
He currently lives in Spain.
