When in the past I came to adjust the drive chain slack according to the manual I noted that the amount of “drop” to allow, depends on the rotational position of the wheel. That is,if the amount of drop is set to, say, 20mm in one position, when you rotate the wheel to another position I found that the “drop” either increases or the chain becomes completely tight.
This to me indicated that the chain pitch had become uneven with use. I was disappointed to note that when I came to replace the chain some time ago the same problem remained which may mean that the problem lies either with uneven pitch even on a new chain or uneven pitch in one or the other of the sprocket wheels.
I do not remember the exact make of the chain I had replaced.
What is the opinion of the group re the above topic?