I'm not a huge cycling fan but I do watch the Tour de France pretty religiously and this is just a prevalent problem. Alberto Contador, the 2010 winner was stripped of his title and just finished serving a ban. Frank Schleck had to withdraw midway through the 2012 race because of doping concerns and Floyd Landis was stripped of his 2006 title. Not that this is an excuse but the physical challenges of riding 150 or so miles a day in July is quite a temptation for some, not to mention the money you can garner if you win.