From the jocular idea that the woman in question, like a hypothetical bicycle shared by an entire town, has had many people "take a ride" (i.e., have sexual intercourse with her).
town bicycle (plural town bicycles)
- (slang, derogatory) A woman who is promiscuous.
- 2010, Jill Myles, Gentlemen Prefer Succubi, Pocket Star Books (2010), →ISBN, page 119:
- "It's not you, my dear. A trip on the town bicycle isn't nearly as fun when everyone's already run it roughshod."
(derogatory) woman who is promiscuous