I have a Raleigh City Sport, Technium frame, with a Sach 2050 rear drum brake that is shot. Anyone have advice on converting it to a disk brake. I'm thinking a mount adapter would be situated about the same place on the frame as the brake strap and the clearance should be okay, But don't know where to go from here. Love the vintage look, but this seems like a better way to go than trying to fix something so obsolete..