In 2012, 198 cyclists started the race. Postma excluded from his batch all those who didn't finish and those who were pictured wearing sunglasses, caps, or beards in their photographs.
Also excluded were those pictured in unusual lighting conditions or not photographed from the front.
Those ruled out from the batch included the winner, Britain's Bradley Wiggins, who was wearing sunglasses in his picture.
This left 104 portraits that were standardised as much as possible, of which Postma randomly selected 80.
Most of the respondents knew next to nothing about professional cycling, additional questions on the survey found.
The three most famous riders in the 80 were known by less than eight percent of the raters -- and 59 out of the 80 were recognised by one percent or less.
Overall, the research suggests that endurance in a man is a big plus for women, a finding that Postma says is consistent with Darwinian theories about mating choice.
During the course of human evolution, hunting success -- and by extension, feeding a family -- depended on a man's ability to chase game for hours or even days.
"That's why endurance performance was a key evolutionary factor," said Postma.
The stamina so prized by women is likely to be reflected in facial attractiveness, goes his hypothesis.
There are also other factors for attractiveness, though, Postma stressed.
No. 1 hunk was Amael Moinard, who on Postma's performance card was ranked a less-than-stellar 42nd out of 80.
"This shows that there is no one-to-one relationship between attractiveness and performance, and there are many other things that affect both a rider's attractiveness and his performance," Postma said.