Originally Posted by
Eric F
With the 11-42, when I adjust cable tension, etc. to work correctly starting from small-to-large it gets progressively worse as it gores across the cassette, to the point where it will skip over 2 cogs, and then have an extra shifter click left at the end. Same kind of thing going in the opposite direction.
I think this (the bold part) is the issue. I bought the cassette off eBay, and the lockring says M8000, but I have no guarantee that the lockring and cassette have always been together. Different cog spacing absolutely makes sense for the issues I'm having. I will reinstall the 11-36 to test this.
I'm going on vacation and taking this bike with me (I hope). It's looking a lot like I won't be able to run the configuration I was hoping. The 38T ring I ordered was wrong (GRX, not Ultegra), so at the moment, I only have a 34T ring up front. I'll make do with that and an 11-36 cassette, If I need to for now.
Grrr....
Sounds like a bent derailleur hanger issue to me. Especially since you were coming from a non shadow Ultegra 6800 RD. A non-shadow RD is more prone to bending the RD hanger especially if the bike gets dropped on the drive side. My old 105 5800 RD setup had the same issue where it'd get progressively worst as you shifted to the low gears. I went to my LBS and had them straighten the hanger out for like $15-30 bucks.