Bike update

The good news is my bike isn't totaled. In fact, it's far from totaled. This last weekend I repaired the damage to my good bike owing to my chain-jump mishap several weeks ago, and I got it into working order for less than $40—and most of the expense entailed buying a chain whip and lockring so that I can do the job entirely at home next time.

That said, it's unclear whether the rear wheel is fully repaired.

Not having the two aforementioned tools to remove a cassette, I took the wheel to my nearby bike shop, with the remaining links of a mashed-up chain wedged between the big sprocket and spoke flanges. The mechanic removed the cassette, which had hidden the extent of the damage to the spoke flanges. At least a sixteenth of an inch of metal had been ground away, exposing shiny and now minimal flanges that now just barely hold the spokes to the hub.

It looks bad but it's only cosmetic, said the mechanic.

I'm mostly sure he's right, but I'm not entirely sure, and that's a big difference when all the chain-side spokes are now secured to the hub by the thinnest margin of aluminum. But wheels are expensive, and I'd prefer not to buy a new wheel on the spot if I mustn't. I should do some wheel-banging curb-jump tests near home before taking it out on a hard ride.

As for the root cause of the chain jump, I think this is no more than a case of the limit screw having been incorrectly set. I blame this entirely on the bike shop where I bought the bike, for limit screws shouldn't need to be adjusted after having been initially set at the shop. My guess is the mechanic who put the bike together adjusted the dérailleur cable but neglected the limit screw. While on my ride I tightened the micro-adjuster, which pulled the cable dérailleur out of alignment and into potential for jumping off into the wheel. Murphy's Law took care of the rest.