Just wanted to say that there are a few things you can do to improve performance of cable discs, largely upgrading pads, but also ruthlessly entering the pads - I normally do this by loosening the calliper bolts, winding in the cable adjustment and the pad adjustment really tight till the rotor is locked in place, then tightening the calliper bolts and backing off the cable and pad adjustment. That should minimise the ab=mount of deflection of the rotor by the pads, which is imo key to getting them working as well as possible. Then burn the pads in really hard - listen for the sound to change, and see if they get grabby at low ish speed. That's about as good as it gets, but give it a go and see if you'd still like to upgrade.