I just picked up an older hardtail Specialized Rockhopper. (Couldn't pass it up. Perfect condition and in a large frame that actually fits my 6'2" frame - $100) I would like to, eventually, put better rims on the bike. It makes no sense to rebuild on my existing hubs as they are not the best quality. Good wheels with compatable hubs are not readily available. The most cost effective solution seems to be to purchase some 9 speed cassette wheels on sale. I assume that means that I would also have to replace the deraillers and the shifters/brake levers. I am willing to do that, but would prefer to not to spend the money all in one shot. Is there any way that I can phase in the conversion? For example, can I configure a 9 speed cassette so that it will work with the current 7 speed indexed shifters and derailleurs? Thanks for your feed back.