I'm converting my bike from 6 speed to 9 speed. As I see I have two options. I can either buy a wheelset or modify my current wheels to accept a 9 speed freewheel. Obviously reusing wheels is cheaper, but I want to make sure the setup will be adequately strong for my 145 pound frame.The plan is to respace the frame to 135, swap out the quick release for a longer threaded axle, and respace the axle in such a way that will minimize how much dishing will be required. Thoughts? For the record, this is for a early 90s lugged Schwinn Crisscross.