Hi roadrocket, Yes, any of the things you mention might be responsible for the wobble, as well as LJ's spindle thought. 2mm - nearly a 10th of an inch - is quite a lot to be out of true on the rim, and if it isn't round that won't help. (Better to try to get to about a quarter of that, by seeing with your pointy device where the biggest gap is, and adjusting the tension of the spokes opposite by either slackening or tightening same as for your race bike. . . ). Then check by ear that all the spokes 'ring' about the same note when you ping them as the wheel goes round, etc etc bore bore blah blah. Putting wheels together is far easier than the mystics who do it for a living would have us all believe . . . but a dial gauge does help and you do have to have measured the offset of the rim from the hub if there is any - which on a front wheel there usually isn't.
Now, that's all well and good, but may have absolutely nothing to do with your problem. I'd actually start from a different and easier angle - called TYRES. If either the front or the rear is not centred properly in the well of its rim, you'll get wobble. Best remedy (to start with anyway and it's free) is to pump them up far too hard - say 3 to 3.5 bar, 45+ psi - then let them down - and then pump them up to usual pressure. If the wheels are out of the frame, bounce them around on the floor vigorously when they are pumped up to the high pressure. (I always do exactly this when fitting a tyre, whether for a car or a bike or even a wheelbarrow or lawnmower, for this very reason). You can see from the lines on the sides of the tyres when the things aren't on right. It is amazing how badly steering is affected by old, hard, out of true - and probably dangerous - tyres. And amazing how many of us try to pretend they're fine, me included because I'm too mean to buy new ones if I can still see the faint outline of the tread pattern. . . .
I had exactly your symptoms a few months ago (bad wobble up to about 30 mph, nothing above that speed) -and it was the rear tyre that was guilty. Replaced it (have fun reading that thread here in Tech Topics!), and the steering was perfect. In the meantime I'd wrongly diagnosed all faults known to man from steering head bearings, fork bushes, wheel bearings, bent rims, misaligned frame, you name it - and they were all OK all along. I envy you your proper front brake! Groily
