Identify the Type of Fallacy in the Following Passage

Identify the type of fallacy in the following passage.
First bicycle rider: How come when we coast downhill you always go so much faster than I?
Second bicycle rider: Because I'm heavier. Heavier things fall faster.
Third bicycle rider: Wait a minute. I thought that was what Galileo proved wrong.
Second bicycle rider: C'mon! That's only common sense. Heavy things are bound to fall faster. Just look at how fast I coast-and I'm the heaviest.