Tour de France
Forgot the link of many others ---> http://www.nytimes.com/interactive/2012/08/24/sports/top-finishers-of-the-tour-de-france-tainted-by-doping.html?_r=0
Ever sport has people that use PEDs, it it probably much less in cycling, now, it seems like a lot but that is because they get tested so much more than other sports, so they get caught.
Haven't watch much cycling in the past. Does the lead pack ever get a big enough lead on the peloton to win?