Some people have a hypothesis of how to talk to women wearing headphones, but what about women wearing racing helmets?
If the woman is a professional racer, use the radio, just as you would for a man wearing a racing helmet. If necessary, tell her where her boyfriend is, so said boyfriend doesn’t wreck her.
If the woman is not a professional racer, then you don’t have a radio, and she can’t hear you anyway, because racecars are loud. Go buy a radio. Even better, go put your own helmet on, because it’s your turn to drive next.