Help - vibrations from front end on new 14s not there with the 13s on

I don't know whether there are any 14" wheels with a small enough center to prevent proper seating, but I'd sure check that.

Recheck your wheel bearing adjustment

"Rig" anything you can for an indicator, and determine if the wheel, the tire, or both are "out."

If the wheel/ tire are out of true, no amount of balancing will correct it.