This 4-5/8" stroke 8-1/2" diameter flywheel assembly replaces the original flywheels in S&S® T124 T2 engines, and fits 2006 HD® Dyna models and all 2007-'16 big twin models as part of an S&S® 124" Hot Set Up Kit®. Sprocket shaft does not have a stock style bearing race pressed on. This three piece design flywheel assembly is for crankcases with Timken® sprocket shaft bearing. Assembly is trued to less than .0005" runout on pinion and sprocket shaft bearing surfaces, making them capable of higher rpm and fully compatible with gear drive cams.