Derailleur gears are expected to withstand external weather conditions and hard continuous stress and transmit the rider‘s shifting impulses smoothly and quietly. Today, high-quality materials and coatings as well as constructive fine-tuning (e.g. x-Bridge) of the chain links enable a long service life with regular chain maintenance. However, the chain should be checked regularly and the chain longation checked with a chain gauge. The wear of the chain is highly dependent on the type of application and the shifting behaviour of the driver. Worn chains also accelerate the wear of the other – usually much more expensive – drive components.