A bicycle chain articulates over 44,000 times per mile ridden. Each movement creates friction between chain plates, rollers, and pins. As parts wear, the chain elongates beyond original specifications. Learning to clean a bike chain properly removes abrasive particles and ensures proper lubrication reaches all contact points.

https://www.pacelinebikes.com/how-to-clean-a-bike-chain-a-complete-guide-to-sparkling-drivetrain-maintenance/