Round R204BT8X BT8 Spindle & 4-4" Bolt Circle Trailer Hub. 4 studs 4" Bolt circle using L44643 inner and outer bearing hub. (BT8 Spindle 1 in.). Includes Hub, inner bearing, outer bearing, seal, grease cap & lug nuts. BT8 Spindle, Spindle base size=1 1/2" Spindle length=3 3/8" Overall length =8 1/4" Capacity (pair) 1,000 lbs. Hubs are cast steel and are not made to be re-drilled or altered. For trailer use only.