Originally Posted by HerrKaLeun

Regardless of if the rotor is rated for metal or not, you still move some of the wear from the pads to the rotor.

Use resin pads and replace those more often, or use metal pads and replace those less often, but replace the rotor more often.

Edit: what really would help install larger rotors. 140 mm is very small. Minimum 160 mm or even 180 mm. Better cooling (temperature fatigues everything, more dangerous than friction itself) and more braking power. At least on the front you should consider that.