just received my new iro mark v the other day. very pretty! this is my first fixed gear bike, and the first bike i've owned in several years. after assembly, i flipped the bike over and gave the front wheel a good spin. i noticed that the wheel wobbles back and forth in the fork a bit.. not enough to hit the front brake, but definately noticeable. is this something to be concerned about? if so, how do i fix it?