Remove the rear drive, clean and lube the splines with each tyre change. Remove the rear caliper assembly, exercise the pistons out. Clean and polish the exposed portion of the piston with brake fluid. Better yet, open the caliper and clean the mother like a pistol. Lube with Brembo grease, seat pistons all the way in. Reinstall with new pads, bleed brake lines with new brake fluid. Brake-in the new pads. The rear caliper on the R3 gathers dirt and requires attention before it locks and you have problems like a hot caliper, locked rear brake and such. Clean calipers well and seat the pad springs correctly. Replace them if rusted. This should be standard service every time the rear wheel comes off. Tyre shops don't do it.