Why do racers wear different types of helmet during an event like the Tour de France?
In the Tour each rider must wear a helmet during regular road stages. . This is a recent rule, which was added for rider safety. However, if the stage finishes on a mountaintop, the riders are allowed to remove their helmets at a certain point of the race on the final climb. The only other helmet they will wear is a time-trial helmet, which is more aerodynamic and built specifically to cut through the wind and provide the rider with less air drag. In a time trial, the rider wears different clothing, rides a different bike, and wears a different helmet, all based around reducing air drag, so the rider provides less wind resistance.
