GEAR SHAFT PART,NUT FLYWHL END BIG TWIN LATE 1981/1988 RPL HD 24016-80  is a Gear shaft nut for Pinion shaft that is used on 1981 to 88 Big Twin models. Replaces H-D #24016-80. These are 3/4"-20 thread. Steel nut is parke  that are very reasonably priced.