I've never understood the reason for this. Once you take an older steel bike and change the fork for carbon fiber and put some sort of deep dish modern wheels on it the ride characteriistics are completely lost so why would you do it?
I've replaced all freewheels with a cassette hub to reduce axle issues but still use box section rims to get the ride quality. I can understand upgrading to index downtube shifters. If you want an all modern bike just go buy one.
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“One morning you wake up, the girl is gone, the bikes are gone, all that's left behind is a pair of old tires and a tube of tubular glue, all squeezed out"
Sugar "Kane" Kowalczyk