Originally Posted by
70sSanO
shift to the 21t and see if you can use the barrel adjuster to dial it out.
Mine seems to be missing the barrel adjuster.
So I've previously ridden along in Cog5 (21T) with E-Tube App in my other hand, making RD adjustments as I bike along.
Between touching cog 4 and touching cog 6 there is no point where cog 5 does not tick twice per revolution.
Regarding spacers, bear in mind this is now TWO bikes and THREE Cassettes, Two Ultegra and a Dura-Ace.
Barry