SKF belt tensioner pulleys for timing system and auxiliary drive are based on state-of-the-art technology. The years of experience accumulated by SKF in the design and supply of belt tensioner pulleys of the world's automotive manufacturers, provide a guarantee of the high quality and performance of each belt tensioner unit included in the SKF product range.

The idler pulley is fixed and allows the belt to be correctly wound around the driven component. When the auxiliary belt drives several components, belt tensioner pulleys are used for guiding the belt and keeping correct tension along the whole length of the belt. The pulley profile is often characterized by one or more ribs.

The belt tensioner unit sets the right tension and provides guidance for the belt. The adjustment of tension during mounting is achieved by means of an eccentric or by means of a spring, acting against a rear plate. The automatic belt tensioner unit, with its built-in-spring and friction system, maintains a constant tension of the belt while the engine is running.