knob knocker
n.— «“Imagine a razor shaving your face, but on a much bigger scale,” says Shawn McKinney, president of the Springfield Area Mountain Bike Association about the knob knocker, a device created to shave the bumps off a mountain bike trail.» —“Smooth moves” by Chris Young State Journal-Register (Springfield, Illinois) June 26, 2004. (source: Double-Tongued Dictionary)
Further reading
Trivia time! Where in the United States can you visit Soda City? If you answered Columbia, South Carolina, you’re right! This nickname apparently derives from an old practice of abbreviating Columbia as Cola. The locals then referred to the town as...
