Old 06-05-19, 06:03 PM
  #21  
JonOnWheels
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However the finish quality of the sprockets doesn't quite look like shimano. Are you certain that's a shimano cassette in your pics?
I have no reason not to trust my LBS. My bike's specs say Shimano CS-HG700-11 cassette, and I have absolutely no reason to suspect the bike shop would have installed a different cassette when they assembled the bike for me. That would be fraud, and I can't believe it would happen. The LBS has been around a long time, has several locations, and is very reputable. I didn't get to keep the old cassette (it has to be returned to Shimano for warranty coverage, per the LBS), and the black cap ring that should say "Shimano" is upside-down in all the pictures I took. But again, I can't imagine that it's not what it was supposed to be.

Maybe they have a take-off 5800 cassette in the back that they'll try to put on your bike for retail.
If you mean "knock-off," no, that didn't happen. The replacement cassette that is now on my bike clearly says "Shimano," which I never doubted, and I didn't have to pay for it.

I don't have much experience looking closely at cassettes, so I can't tell how worn the old one was. But the LBS owner and his mechanics are all very experienced, and if they tell me the inner cogs are shot, I have to believe them. Since they're sending the cassette back to Shimano for inspection, they're obviously quite certain about it.

Beyond all that, when I pull a cassette because it's noticeably worn (that is, shifting has begun to suffer,) the 11, 12, and 13 are usually in pretty good shape, because they don't get used nearly as often as the 5 cogs in the middle.
...And that's what's so strange here. The mechanic was certain that I was riding only on the smallest cogs because those are the only ones that appeared worn to him. I know I don't do that. While it makes no sense that any cogs would wear out so quickly, it makes particularly no sense that it would be the smallest cogs. That's why I posted the question, to see if anyone has a theory how this could have happened. The bottom line is that it did happen, and I'm trying to get a handle on why.
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