Tensioner and deflection pulleys allow optimum belt guidance around the driven units. They also ensure constant belt tension – in all engine operating conditions. In addition, the rollers are used for calming critical belt sections and serve to avoid collision problems with the surrounding construction.

Deflection/Guide Pulley, V-ribbed belt

Increases the angle embraced in belt drives.
Gives tension to the belt and transfers the driving force of the crankshaft.
Compensates for the elongation of the strap, typical over time.
Allow for shorter wheelbases.
Prevents belt slippage.

The belt tensioner helps to ensure that the belt to which it is attached works perfectly under all circumstances. If the tensioner were to fail and allow the belt to lose its tension under heavy load, catastrophic damage could ensue to the engine or other components could simply stop.

Hybride tensioner