Patented damping mechanism provides maximum stability, reducing vibration and increasing the life of the belt, tensioner and other accessory drive components Patented labyrinth seal prevents contamination of internal parts for maximum durability and service life Patented design provides superior belt alignment and tension for improved drive efficiency and life Long-lasting steel pulleys with dust shields to protect internal bearings from contamination Double row bearings carry more load and last up to 3X longer than two individual bearings Chrome-silicone round torsion spring for less flex-fatigue than flat-spring designs Optimized components engineered for maximum strength and durability

FleetRunner Heavy-Duty Automatic Belt Tensioners are the longest-lasting belt tensioners in the industry, engineered to exceed demanding OEM requirements. In laboratory tests under extreme peak-to-peak vibration and contamination tests, FleetRunner heavy-duty tensioners lasted up to 3X longer than competitive aftermarket tensioners.