Break in period is non-existent besides grinding them down and gettin the groove going.
Also, in response to j soy, yeah I’ve had too many pairs of trucks of all different companies that had one side of the axle with longer threads. These new Aces are perfectly even on both sides, but they seem longer than before. Using one speed ring on the inside and out like normal and having some good space for the wheel to go back and forth, the axle sticks out a with a couple threads. Two rings on the inside will solve it though.