Re: Bite the bullet
Flat tires are a real hassle. Try using one of those Kevlar belted tires like the Maxxis Overdrive. For the wobbling sprocket, try to tighten the bolts and nuts at the same time, opposite nuts at a time. Takes a lot of patience...
Regardless if it's left or wrong, the opposite is always right.
Caution: This hobby is habit forming.