Well I’m just about getting to the end of my patience with mine.
After building mine onto a new tt bike it just would not shift/index correctly everything was checked when building it up derailleur angle etc , road tested it but as stated before up thread in the middle of the cassette if you get it to change up correctly it won’t change down so you end up going down 2 gears then have to come back up one to get the gear you wanted , if you get it to change down the opposite happens .
So as it worked ok on the other bike a few weekends ago I’m thinking what’s going on
So I realised it was a different rear wheel , so I put that in and it worked .
That’s that sorted I thought must be the freehub or something .
Wrong , the wheel which worked was a Zipp 202 with a HG11/34 rear cassette(it was a road/gravel event I did hence the cassette and I use a long cage rear mech) when I put the 11/28 cassette on would not index again
tried 2 other cassettes none worked.
Then put the gh800 cassette on the original wheel (303zipp) it worked .
Tried in another wheel Hg800 cassette = worked , put on any std Dura ace, sram, ultegra cassette and it does not.
That’s 3 hours of my life
Tooth profile on the hg800 cassette is different disigned for mtb 1by11 as well as road much steeper ramps/tooth profile.
So I can use my Etap but if I use anything other than a 11/34 hg800 cassette (and that’s the only size they do as far as I can tell ) it won’t index .
Remember I’m on my 2nd rear mech , 2 different bikes .
Thought provoking.