Originally Posted by yannisg

I installed the RD-8000 together with the 34 tooth sprocket on Ultegra 6800 shifters a year ago.
I must of installed the RD in the correct position because I noticed how short the distance was between the end of the chain stay cable housing entrance to the barrel adjuster.
I had no problems shifting.
Recently, I replaced my old shifters with Ultegra 8000.
I removed the RD to check the hanger alignment which was ok.
When I re-installed the RD I must have inadvertently placed the butting surface on the hanger between the upper and lower RD notches.
In this position, the housing was longer.
I went for a ride did a couple of adjustments to the barrel adjuster, and all was well.
A riding friend with the same bike and RD had the setup as I originally had it.
That puzzled me so I posted the question.
When the reply came I re-installed the RD according to Shimano's dwg with the lower RD notch butting against the surface "z" on the hanger. I had a hard time installing the inflexible cable housing within such a short distance; I need to get some flexible cable housing.
Went for a ride did some minor adjustments and all was well.
Shimano indicated that there should be no gap on surface "z" because the gap could affect shifting.
I don't know how much the RD would rotate if tightened within specs.
Also, what is the upper RD notch for; a possible different setup.
I can't say the shifting was any different between the 2 setups, but maybe in the long run it would be.