Some additional follow up . . . I received a prompt response from Khang Vo . . .

The material composition of the grooved part on all of the Karmen 62mm pulleys is stainless steel . . . not hardened steel. Sorry for my prior incorrect references to "hardened steel". The important fact is that they are NOT aluminum.

Also to ease the minds of most of you using the Karmen 62mm pulley that were from the production run purchased directly from Rudy . . . Khang Vo confirmed that those pulleys Rudy distributed were an "improved" version . . . different from the original "test" pulley and a limited quantity of originally produced pulleys.

I am not aware of ANY of the "improved" pulleys (the one's Rudy distributed) failing so you guys running those should have have restored confidence in the quality and reliability of those pulleys.

I think this new information pretty much closes out this topic. Unless I discover something of additional importance, I am ending my research on this . . .