Invention and Engineering
A bicycle wheel is a wheel, most commonly a wire wheel, designed for a bicycle. A pair is often called a wheelset, especially in the context of ready built "off the shelf" performance-oriented wheels. Bicycle wheels are typically designed to fit into the frame and fork via dropouts, and hold bicycle tires. A typical modern wheel has a metal hub, wire tension spokes and a metal or carbon fiber rim. The hub consists of an axle, bearings and a hub shell.
Emilia-Romagna.
Gauge block.
Text from Wikipedia; plate via Wikimedia Commons. Text CC BY-SA 4.0; plate freely licensed (see Commons). Source record. Images and catalogue data are reproduced from open-access collections.