Here are the predictions for the maglia rosa (pink jersey) for overall GC victory in the 2015 Giro d'Italia.
Here are my predictions for the maillot jaune (yellow jersey) for the general classification (GC; best overall time) and for the maillot verte (green jersey) for most sprint points in the 2014 Tour de France. You can compare them with the results of my predictions for the maglia rosa (pink jersey) for best overall time in the 2014 Giro d'Italia.
My usual practice is to assign "odds" or probabilities for winning the general classification, which typically produces a list of about 25 or 30 riders. (Technical Note: Since the cumulative probability cannot be bigger than one, I spend a ridiculous amount of time tweaking these probability assignments to make sure that this constraint is observed.) The probabilities are mainly used to rank the selected riders.
But the real question is: after the race is over, how do you tell if your predictions were any good?