shelby: When you say, surprised, are you surprised that I was able to ride with it in that condition for three weeks problem free? Certainly was not that.
Here's what happened.
Frame was damage free up to this point...
2 days into this chain replacement, I dropped it once. pulled it back up around the chain keeper, and scratched up the frame.
Then did 51 miles with 6000' of climbing... After that, the fun began, with drops, almost anytime I went into attack mode. Brought the bike back to the shop, 3 different times, in 10 days, with them addressing OTHER issues, other than the wrong chain size. After I complained about it to a different shop, the guy realized that I was riding with an incorrect chain. This is after I nearly snapped off another derailleur hanger, and split the derailleur pulleys enough so that they fell out of the RD. So, I managed to ride three weeks on it, but you couldn't consider it smooth. I knew something was up, but didn't think I needed to check the work of mechanics that I thought knew what they were doing. In any case, all those pullouts resulted in a badly damaged carbon frame, that I'm none too happy about. AFTER the initial shop replaced the chain, the big chainring, things settled down until a 77 miler (less than a month later, chain at 1/2), where I dropped two times, and couldn't get the chain around the chain keeper (which I assumed was there to keep the chain from dropping inside, and damaging the carbon frame..). In those cases, I shifted without load, and it dropped, then was coming down a hill, stopped, and it dropped, as I started up again. The next day, the shop I bought it from (#3 in this story) took a look at the frame and said, "nope, don't ride. Repair or Replace"
So what I wonder is:
1) Predictably the chain will drop more, if it is ill fitting, like when one puts a 10sp chain on an 11sp drivetrain.
2) Chains will drop when you try and shift under load (I put that one to bed in January)
3) Does a chain keeper (I have a trek, or had) need to be adjusted when a new chain, chainrings, cassette are replaced.
I think I need to be just as well versed as any repair shop is considering I ride as much as I do, or at least check ALL their work before walking out of the shop.