I finally installed new ultegra rear D on my 105 bike, except I didn't. Checked my new chain length x3 but new D (it's the larger medium ultegra which should work with 11speed ultegra 11-34 cassette) interfering with cassette.
I did new rear cable with new internal routing too, so checked tension, and chain. The B screw is right in, feels like there's something goofy with the hanger, that it may need a different type as the ultegra R8000 D is different shape to R7000 105. Checked giant website and it doesn't appear so...any bike boffins got tips?
Hmm...so put back on the 105 and shifting like a dream.
I noticed a little wobble to crank, investigated and found non drive side bearing running rough, so ordered a new complete bb71 pressfit, will change it out
Now I have the ultegra front & rear Ds in box, one of the house bikes has older ultegra so will keep as spare if I can't figure it out