Koppenberg is a hill in the Flemish Ardennes, Belgium.
The ascent was part of the Ronde van Vlaanderen since 1976 but was excluded after the crash of Jesper Skibby in 1987.
Koppenberg isn’t the longest (692 m) or the steepest (9% average with a section of 22% as maximal steepness), but most likely the hardest hellingen of the Ronde. According to Edward Pickering:
“It’s the combination of gradient, narrowness between two steep banks and one of the worst stretches of cobblestones make the Koppenberg such a formidable obstacle.”*
In 1987, Skibby rode solo at the head of the race, when he reached Koppenberg. He had an advantage of two minutes, but climbing the hill he became slower and slower and the peloton came closer. The car of the race commissaire followed Skibby so close, that when they wanted to move away, the car knocked Skibby, who fell to the ground. The car run over his back wheel and narrowingly missed his legs. Skibby’s race was over.
After widening and re-paving the road, Koppenberg was re-introduced to the race in 2002.
* Pickering, Edward: The Ronde. Simon&Schuster UK. (p. 108)