Okay, something weird is going on. I rode the bike to work this afternoon and the shimming/wobbling was greatly diminished when I tried to induce it. Still there, but barely noticeable. The only difference between this morning and this afternoon was that I had my tail bag on the rear of the bike coming to work. (weighs maybe 10 lbs) It does appear there might be something misaligned with my rear wheel, perhaps? I'll adjust my chain to doublecheck the rear wheel alignment. Pretty weird.
