Shimano Change wheels Deore M6000 set

Replacement pulley that is identical to the original. The derailleur pulleys ensure the tension and guidance of the chain during gear shifts. The upper pulley is referred to as the pulley and is responsible for the movement of the chain, while the lower pulley, known as the string, is responsible for the tension of the chain. Therefore, for a precise and smooth cassette change, the derailleur pulleys must be in perfect condition.