Wingsmoto Heavy Duty Chain Roller Tensioner w/Spring 110cc 125cc 140cc Pit Pro Dirt Bike Heavy duty chain roller tensioner with upgraded spring, thicker wire and longer travel The bracket use 3.2mm thick metal, stronger built than other tensioners. The kit comes with an extra roller as spare parts. Seamless steel bushing brings smooth rotoring and longer life. 14mm inner diameter mounting bushing size, please see photos for detail measurements.