There are two types of belt tensioners: manual and automatic. Manual tensioners require user intervention to adjust the belt's tension, while automatic tensioners maintain optimal tension without user intervention, which can extend belt life and reduce maintenance frequency.

Two types of belt tensioners may refer to manual and automatic belt tensioners. These terms refer to the mechanisms that maintain the correct tension of the belt in a machine or engine.

Manual tensioners require the user to manually adjust the tension of the belt. This is a difficult process and, if not done correctly, can result in insufficient tension, which can cause the belt to wear or break prematurely.

Automatic tensioners, on the other hand, adjust themselves to maintain optimal tension on the belt without user intervention. This can extend the life of the belt and reduce maintenance frequency.