I had a lot of problems with noisy drivetrain on my IRO, in my case I think it was a cog issue... Just chucked an EAI steel cog (to replace a Condor one) onto my Phil and it's completely silent now...
IRO BB + Sugino 75 crankset + HKK Vertex chain + EAI cog + Phil Wood = Silent running
I had a lot of problems with noisy drivetrain on my IRO, in my case I think it was a cog issue... Just chucked an EAI steel cog (to replace a Condor one) onto my Phil and it's completely silent now...
IRO BB + Sugino 75 crankset + HKK Vertex chain + EAI cog + Phil Wood = Silent running