I bought a tektro kit for disc brakes, not knowing what is involved. I realized after getting the kit that it's a bolt on for a bike that already has disc brakes.
Mine is clamp type. I got a used wheel from a bike shop that the rotor bolts up. Now I need to weld a caliper mount to my forks and use a longer cable to route there.
Now I'm waiting as I want to do a suspension fork (or a new frame) as I have an old dept. store bike that nothing is compatible with. I believe the disc front will work much better than the old clamps.