Tensioners are belt tensioners used in automotive drivetrains. The structure tensioner is mainly composed of a fixed casing, a tensioning arm, a wheel body, a torsion spring, a rolling bearing and a spring bushing, etc. It can automatically adjust the tensioning force according to the different tightness of the belt, making the transmission system stable, safe and reliable. We are the manfacture  of the Automotive bearing ,our products are wheel bearing, tensioner pulley, clutch release bearing and other kinds of bearings .so can supply the high quality and best price.