the split sprocket is from gokarts it uses a #35 chain and can be of any tooth # such as a 68 tooth or a 70 tooth or a 75 tooth such as the one I am using,., the 68 tooth I use for flat land use moves along pretty good the 75 tooth sprocket I am using is pretty good at climbing the hills around this area . I made the adapter so I can change the sprockets and not have to remove the wheel , just 6 bolts ,and put on the other sprocket then extend or shorten the chain as necessary the change takes about 15 minuets and I'm rolling again