I have a Schwinn Panther circa 2004 that NEEDS better rear brakes. I have converted it to 9 speed and added v-brakes to the front. It has a pitiful "U" brake on the rear and no other hangers for better brakes. Is there a a way to mount a disc caliper? My Deore freehub is disc compatible. I would consider a roller brake if disc is impossible. I am new here and I did try a search before posting. Thanks in advance.