Interesting, I just replaced the cables on my 5700’s this weekend and thought as I put them back together and re-wrapped the tape that the shifting didn’t show the massive jump that normally results from a new cable.
I came to the same conclusion, dumped a load of GT85 in there and clicked up and down with no cable for 5 mins. Seemed to get a bit better, but the difference between old and new cables is nowhere near as dramatic as with my (older) ultegras after a cable change.
Just checking (and I’m sure you know) – there are 2 exits for the gear cable – one in a straighter line round the back of the bars and one with a tight turn to run round the front of the bars…..whilst the front gives a nicer profile, its definitely worse for the friction of the cables.
Next time I might try the oil batch / boiling water – has anyone actually done the boiling water without damaging anything?