I bought a rockhopper frame and J3 when i put my front wheel on it isn't centered between the shocks. What's wrong? Is it supposed to be offcentered? This is my first bike to build and first shock to have disc brake mounts. It is a mavic crossland disc and v wheel. i'm not using discs, but Vs. The wheel sits straight in my old Judy SL. any help would be greatly appreciated.