What is the name of the quick-release mechanism for bicycle wheels invented by Tullio Campagnolo?

The quick-release mechanism for bicycle wheels invented by Tullio Campagnolo is the quick-release skewer.

A quick-release skewer is a thin rod that passes through a bicycle hub. One end has a threaded nut, while the other carries a cam-operated lever. Closing the lever clamps the wheel securely into the fork or frame; opening it allows the wheel to be removed without a wrench. “Quick release” describes the system, while “skewer” identifies the rod-and-lever assembly.

Campagnolo conceived the design after a frustrating race in 1927 at the Croce d’Aune pass in the Italian Dolomites. Cold weather made it difficult to loosen the wingnuts securing his wheel, costing him time during a gear change. That experience inspired a faster wheel-retention system. He patented the cam-mechanism skewer in 1930, and Campagnolo produced its first quick-release hubs in 1933.

Quick releases were once common on road and touring bicycles. Many modern performance bikes instead use through-axles, which are stiffer and better suited to disc brakes. “Skewer,” “cam release” and “quick-release lever” describe parts or features, but the complete mechanism is the quick-release skewer.