 is an asymmetric damping tensioner belt drive system having an asymmetric damping tensioner. Another aspect of the invention is to provide an asymmetric damping tensioner belt drive system capable of providing a higher belt tension during rapid changes in engine speed. Another aspect of the invention is to provide an asymmetric damping tensioner belt drive system having a greater damping friction in a loading direction than an unloading direction. Another aspect of the invention is to provide an asymmetric damping tensioner belt drive system having a coefficient of asymmetry in excess of 0.0. 