Penny-farthings were a form of bicycle.
A penny-farthing on the Morok mind-reader's screen. (TV: The Space Museum [+]Loading...["The Space Museum (TV story)"])
While strapped into the Morok mind-reader, the First Doctor was questioned by Lobos on how he came to Xeros. He thought of a penny-farthing and an image of one appeared on the device's screen. (TV: The Space Museum [+]Loading...["The Space Museum (TV story)"])
The Eleventh Doctor stated that he once saw a tandem penny-farthing. (COMIC: The Sound of Our Voices [+]Loading...["The Sound of Our Voices (comic story)"])