Originally Posted by mihlbach

The 1st gen sram red cassette is hollow. It transmits noise more than cassettes of traditional design. Because cassettes are designed differently, the amount of noise that you hear may not have a direct relatioship with efficiency. FG cogs, on the other hand are all solid steel and should transmit noise about the same.

I have a sram equiped bike. It don't find it to be very noisy, but i don't have a red cassette either. I have no particular love for sram, but whats the deal with all the sram hate.