R” Hubs – For Assembly With “AR” Plate Sprockets
Circular bore hubs have regular keyway and 2 setscrews. Sq ., Hex and Splined bore hubs have got set screws only.
Ready Sprockets are an assortment of sprockets and hubs drilled and READY SPROCKET HUB – TYPE R tapped for simple, convenient assembly with standard hex head cap screws. For No. 35 through No. 100 Chain, with share finished bore hubs to accommodate shaft sizes 
through 2-3/4″ diameter, and also a variety of square, hex, spline, and tapered crucial bores.