I have a slight knocking noise in my front right caliper. Its only noticable at low speeds up to about 30 but I'm sure its still doing it at higher speeds.

When I took the wheel off to check it appears that the rotor is catching ever so slightly on the outside pad and just making it move up and down a fraction of a fraction of an inch in the caliper and this is the source of the noise.

Any ideas on what might have caused this and what can be done to correct? and if its worth worrying about as I'm going on a 12,000 km road trip on Friday.

The rotors and pads where replaced this past March...??

Brian