Ok, bought an XT 12sp mech to try on 11sp drivetrain after talk that it’s compatible. Hoping that being designed for a bigger cassette, it would reduce the excessive B screw needed on Felix’s GS 11sp xt to clear the 10-46t 11sp cassette nicely while still having acceptable shifting.
New inner/outer. New chain, set to correct length as per instructions, but just couldn’t get it to shift and mesh cleanly.
It’s the long cage model, but instructions said it fine for 10-45.
But nope. Played with B screw, just couldn’t get it to mesh perfectly through the range. I’m fussy, but seems like the pull ratio is just a bees dick out to me.
Checked the hanger, it’s straight.
Banged back on the 11sp mech, all bonza again.
Didn’t have all night to fart around as Felix needs the bike in the morning, so might try it another day on a spare bike, but would love to know what I did differently to others who say they’ve done it and got it working