So I have Campagnolo Athena 11 speed chained to a trainer with 11 speed 105.
For those afraid of Campagnolo this should not be an issue at 11 speed.
In the sixth cog it’s fine, middle, so Erg mode is great and I work out fine through winter.
Upper and lower limiters are set appropriately, derailleur aligns okay to top middle and bottom cogs but away from the middle it clunks…
On the race wheel, it doesn’t.
I’ve analysed it and can see that as the chain leaves the largest cog and returns to the chainring it slips into place and clunks every few seconds, quite clearly. Can’t see it on the smallest but assume the same thing is happening.
I run a similar set up (Campag Chorous 11sp on a 105 trainer cassette) the clunk only comes for me under resistance and a certain cadence; its pretty regular when it starts though. I had thought it was the cleats but its interesting it could be something else :-/