Originally Posted by UngaWunga
I figure if it was a stuck piston, the rotor would flex to one side of the other, away from the unstuck piston. I'll double check everything.
Ive personally had this problem once. but the brakes worked relatively well still... But we deduced that the inside caliper pistons would push out on the disc so hard and outer ones weren't, and this caused the disc comes loose after a while. I ended up having to buy a new hub, for my gasgas...
Plus what you say, it is pretty hard to see from the riding position
but sure is worth checking. it was just dirt caked in the calipers/pistons over time... I don't allow myself to "try to use all of the brake pads" anymore. when thin, I change, learned an expensive lesson, that 20-30 dollar brake pads would save.