Round R50642X 42 Spindle & 8-6.5" Bolt Circle 9/16" Trailer Hub. 8 studs 6.5" Bolt circle using 25580 inner and 14125A outer bearing hub. (42 Spindle). Includes Hub, inner bearing, outer bearing, seal, grease cap & lug nuts. 42 Spindle, Spindle width =2 1/4" Spindle length=6" Overall length =11 1/16" Capacity (pair) 5,000 lbs. Hubs are cast steel and are not made to be re-drilled or altered. For trailer use only.