My son thinks he is interested in trying bicycling as a new sport. I have an older (1980's) Bianchi (cro-moly) bike with downtube shifters. Since I would like him to experience index shifting, can a bike like this be practically converted to index shifting. This is seen as temporary measure to see how he likes biking. If he really gets into it, then we will buy him a new bike after a few months. Is this practical or should we just forget the old Bianchi and buy him a new bike? I hate to buy him a new bike to have him lose interest after a few rides and, if he does get into it, he will want a better bike than we would buy him as a beginner. I would hate to have to buy 2 new bikes in only a few months. Suggestions?