Set of 2 bicycle derailleur pulleys Tiagra 4700

Replacement roller identical to the original. The derailleur rollers provide tension and guidance of the chain during gear changes. The top roller is called the "puley" and is responsible for moving the chain, while the bottom roller, called the "string", is responsible for tensioning the chain. The derailleur rollers must be in perfect condition to ensure precise and smooth gear changes.