“DSR” Hubs – for assembly with “AR” plate sprockets to create double-single of substance sprockets. Finish bore hubs possess READY SPROCKET HUB TYPE DSR standard keyway and 2 setscrews.
Ready Sprockets are a variety of sprockets and hubs drilled and tapped for simple, convenient assembly with standard hex head cap screws. For No. 35 through No. 100 Chain, with share completed bore hubs to accommodate shaft sizes through 2-3/4″ diameter, plus a 
variety of square, hex, spline, and tapered key bores.
