Rubbing disc brake caliper Finally I bought my new hydraulic disc brakes (Shimano M-446) and installed it on my bike . It was a little difficult to adjust the calipers  , because the space between the pads is smaller than on my previous brakes (Hayes Stroker Ryde). But finally I had managed to align them properly and went for a test ride . When I sat on my bike I heard the rotors rubbing but only on cornering and turns . I got out of it and rotated the wheel but everything was OK when. What a mystery ? Why the rotors are rubbing only when I am sitting on the bike ?
There could be some play in the axles. Lift the wheel and try to wiggle. Another explanation might be a 'soft' fork. Also check the tightening of the quick releases, a quarter turn of the nut might bring some change.