A HERTH+BUSS JAKOPARTS brand Tensioner Pulley, timing belt is a part of the timing belt drive, which serves to bypass the belt in a certain place or several places and is a freely rotating pulley of small diameter.

The composition of the roller is small: it is the roller mount, the internal rolling bearing with a protective oil seal, and the working body of the roller itself, which is in contact with the belt.

1. SUPRA (_A8_)
2. GS (JZS147_)
3. GS Saloon (JZS147_)
4. GS (_S16_)
5. GS Saloon (_S16_)
6. IS I (_E1_)
7. IS SportCross (_E1_)
8. ARISTO (_S14_)
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The principles of the timing belt tensioner work

Excessive tension leads to intensive wear of the timing parts - pulley bearings (water pump, generator, tensioner, etc.), the belt itself, and others. In addition, a tight belt stretches faster and shortens its service life. Too little preload is fraught with more serious problems - slipping of the belt along the toothed pulleys of the camshafts, which leads to a violation of the valve timing and deterioration of the entire engine.

Therefore, a tensioning device is introduced into the timing drive in the form of rollers of one design or another, which, during engine operation, maintain an optimal belt tension.