No special tools are required. The ribbed belt is not a stretch belt. The tensioner pulley is mechanical and the tension is adjusted with a single bolt (head facing down). The access to adjust the pulley is abysmal and very frustrating at best. Do some searching and you will find that I removed the adjustment bolt and cut a slot in the threaded end. This allows the use of a screw driver to easily run the bolt up or down. Breaking loose/tightening still done with proper wrench.