I beg to differ. I have been on a 7075 alloy cog (Starf*cker?) since September 2009. It is frighteningly light, but it's running strong on its fourth month.



I think it could be because my COG is 19T and is big. You might get different results for small cogs. But you know, alloy cogs have been around for good long time now. There are NJS alloy cogs. The new Sugino cogs (/w splines) are aluminum, too.

But I wouldn't go with the aluminum lockring. I am worry about cracking there. Cogs are thick block of metal, but lockring is ... a thin "ring" of metal you see?