Sticky piston? The SRAM brakes run quite close to the rotors (guessing that's why they sold you a SRAM rotor) make sure the rotor is true, spin the wheel and listen for rub, eyeball the rotor down through the caliper and bend rotor in the appropriate direction, keep doing until all is well, a small, clean adjustable spanner makes a good substitute for the proper tool, or very clean fingers in s push. You can also take the pads out and give the spring a bend outwards, sometimes that's enough to keep the pads slightly further from the rotor.
Sticky piston? The SRAM brakes run quite close to the rotors (guessing that's why they sold you a SRAM rotor) make sure the rotor is true, spin the wheel and listen for rub, eyeball the rotor down through the caliper and bend rotor in the appropriate direction, keep doing until all is well, a small, clean adjustable spanner makes a good substitute for the proper tool, or very clean fingers in s push. You can also take the pads out and give the spring a bend outwards, sometimes that's enough to keep the pads slightly further from the rotor.