Did you torque the lug nuts properly?

In the old days you could tighten them right down and it didn't seem to effect anything, now a days with everything being lighter and thinner torque is very important.

Sometimes you can get away with just re-torqueing them, if that doesn't work do a run out check on the rotors, no sense turning all the new rotors if just one or two are causing the problem.

Tox!