Chain ring question

[ny biker]

Still working on this. A few developments.

A friend sent me a link to an article on choosing chain rings, but I haven't had a chance to read it yet. Hoping to get to it today.

While out riding the other day I was thinking about how rarely I use the 11 cog on my cassette. So now I'm thinking the new one will be a 12/32 -- 12-13-14-15-17-19-22-25-28-32 (as compared to an 11/32 with 11-12-13-15-17-19-22-25-28-32).

But the big thing is -- the cassette currently on my bike is not actually an 11/28. I got down on my hands and knees this morning with a magnifying glass and a flashlight to look at the cassette that's now on the bike, and the cogs are labeled: 11-12-13-14-15-17??-19-21-23-26. (The 17?? is the cog that I can't see right now because the chain is in the way. Most likely it's a 17.)

The original bike specs say it came with an 11/28 -- I can find a post on this forum from when I bought the bike where I discuss the differences between the new bike and my old one, and it clearly shows I was expecting the new bike to have 11/28. The cassette has been replaced once or twice since then and I always thought the mechanics at the shop put on a new cassette that was the same as the old one. So either the bike originally came with the wrong cogs or somewhere along the way someone changed the cogs without telling me. Maybe this was just a simple mistake, or maybe there was no 11/28 in stock at the time it needed to be replaced and someone was just being lazy and using whatever cassette they had available without asking me first. Either way I'm feeling... not mad, but definitely upset. I have always trusted the people at this LBS. I'm not sure what I will do about this; I will definitely point it out to someone at the shop, since it's a quality control issue. I just haven't decided yet if I should email the owner directly or talk to someone else.

Assuming the bike's original cassette was really an 11/28, I probably didn't notice the change to totally different gears because it was most likely done over the winter when I wasn't riding as often.

I'm really disappointed by this.

Anyway, I will rerun Sheldon Brown's calculator with these numbers. But the big thing is that my largest cog right now is NOT a 28 -- it's only a 26. Trying to look on the bright side -- I will be gaining two easier gears than what I have now when I make the change.