i just got a fuji espree but the tire pop and found that the wheels are not trued at all. so i am just looking for lighter wheels and a maybe a group set. the only thing that i found to be compatible is a shimano 600 6 speed cassette.

i am wondering if i can put a cassette with more cogs. or take a "modern" rear wheel and put spacers and just have 6 cogs on it so that way it will have lighter wheels but still be able to fit between the chain/seat stays. i tried to put a 10 speed wheel but the small cog was prevent that from happening.

i just want to know what are my options because i want to put on better components on the bike. i may just keep it stock and appreciate the bike as is. the bike gods would like that wouldnt they?