I'm wondering if anyone would know why my brakes are scratching against the discs on my bike... It's happening on both the front wheel and back wheel but worse on the front. As I push the bike forward the sound changes from softer to louder and softer again, so it's obviously worse at one part of the disc than others, suggesting my disc is warped but as far as I can tell by looking at them both discs look fine. Looking at the brake pads I think they are cheapies ( I recently bought the bike), and have 2mm left on both the front and rear. The service limit in the manual is 1mm. Also, the pads on the back seem to be unevenly worn. One side of one pad has more left than the other end of the same pad, and it's the same with the second rear pad. I wonder if I need to replace the pads, replace the discs, bleed the brakes etc... Any advice would be appreciated Thanks.