[IdahoDoug]

I wouldn't chase the "old pads" thing too much. One 10 minute bedding procedure as described on various websites will properly distribute pad material to rotor and vice versa. In addition is the statistical unlikelihood that areas of grip/less grip as you go around a rotor (the only thing of concern there) would randomly line up with each other on the two front brakes to cause a shimmy. It is just as statistically likely that these grip variations would either cancel each other out, or be close enough that their frequencies are within the resonant frequency of the wheel/tire. In other words, you can't wobble a heavy assembly like a wheel/tire if the forces are too close together in time. Knowing this, to the OP - if you're feeling the frequency of the wobble changes quite a bit then let us know. However, the "grip/no grip" issues regarding pad/rotor interface would more likely manifest as "pulsing" type feelings at many speeds and be more obvious/noticeable at slower speeds. I'd focus on the other stuff first and certainly don't mess with pads by cutting them etc at this stage in the diagnosis. Creates too many variables for a low probability solution. HTH....