I've seen them but can't locate anything available or in stock. I have 11:54 as my current primary reduction, My dilemma is that my secondary drive sprocket is too small "24t" and the chain is dropping on pot holes catching and it destroyed a decent Alivio derailleur among other things on my last ride. 35 mph and that noise scared the crap out of me. I was lucky that the spokes didn't try and eat the chain/derailleur throwing me off. So after that short rant. Im going to up size the secondary sprocket substantially but I need to maintain my current motor reduction or real close to it. So the 72+ tooth t8f sprocket for a freewheel is where im falling short. If anyone has a line on where they could be purchased that would be awesome!