These hubs are 3/4" ID 3/16" keyway with a 4 on 4 bolt pattern.. When ordering these hubs allow 2 - 3 weeks because they are all built when ordered at this time. The hubs are best held on by a bolt in the end of the axle and a shaft lock behind the hub or shaft locks on both sides. You can add a 3/4" reducer bushing for $15, it is welded to a hub so you can use a 1 1/4" disc mount from a cart. click on the pull down box for the option. The price for these hubs are   $25.00 each or $40.00 each for the hub with the reducer bushing.