Ok I am coming into this thread a bit late but do have a serious question. I just spun a 17T cog on my freewheel flip side so I can have a fixed/fixed set up. One of these days I will get an old BB lock ring for it but so far it works fine. I just tightened the thing on and went right out to a hill and hammered up it to tourque the cog on. Now I don't know the engineering behind it but it seems to me that will tighten the thing greater then both the rotafix method or a chain whip. Yes? No? So I don't see what the discussion is all about. If I climb an 8% grade on a 46x17 there is more tourque applied to the cog then what I could get with a whip or rotafix I would think?