You guys were awesome with the last problem, so here's a trickier one for you. First, a little background:
The bike is a pedal-assist electric and weights about 40 lbs w/o the battery. I had it on the roof of the car, and like a dolt, tried to drive into garage. D'oh! The rear wheel had a four inch flat spot, the rear rack has a big ding, and the basket hanger on the front (yeah, its got a basket..sue me ) got nicely squished, but otherwise she looks pretty good.
Ever since the crash, I can't keep the chain tensioned. The drive side axle nuts keep getting seriously buggered, like when they finally give out and the chain falls off, I unscrew the nut and end up with a few full threads embedded in the axle. Ouch.
Surprisingly, the axle seems to be holding up OK and the threads show very minimal wear (a .5 mm by 2 mm patch is slightly silver where the rest of the axle is black). I've actually tried another wheel in there (I had a spare Nexus'd wheel) and the same thing happens.
On the advice of a mech, I checked the dropout alignment: Looks perfect
Can anyone think of a reason why this is happening?