I believe that peloton means the main pack of riders. In a race you would have the superhuman leaders out in front, then the rest would be grouped together in the peloton.
The definition at dictionary.com says that it is a small military group, or platoon.
It comes from the french word for "small pellet".
Someone please correct or elaborate if necessary.
Lance Armstrong was far ahead of his team, most of whom were in the peloton.