Knowing me and my well used memory, I believe that my hubs, front and back, run pretty darn quietly. I cannot hear them while riding. As for the freewheel making noise...
All of my Campy ones make clicking noise when coasting but some of my Shimano freewheels do not make much of a sound at all. Perhaps my hearing is worse than I thought.
Anyway, are some freewheels quieter than others and, are some quieter to the point of being silent?
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"98% of the bikes I buy are projects".