On this parts fiche the Spring,5.5x0.7x18 is the most specified component.
The sub assemblies and components that make up this Gear Change Mechanism include this Lever-change,pedal, the most expensive part.
A sample from the products for the Gear Change Mechanism include: Bolt,socket,6x16, Spacer, Spring,5.5x0.7x18, Collar,return Spring.