I bought my bike last year, used, from Craigslist. It was built up by the guy I bought it from and has a record/chorus 10 speed mix. Record shifters, hubs, FD. Chorus crank and RD. I was thinking about this yesterday and was wondering what might have been the purpose of mixing it? Was there not much to gain by making the crank and RD record also and therefore not worth the extra cost? Is there no obvious reason? What might the guy have been thinking when he built it?