My question doesn't touch an important practical topic, but just for the sake of discussion:


Chain length should not affect B screw adjustment because if you modify chain length, the cage of the derailleur will only rotate around the center of the upper pulley. It means that the center of the upper pulley will not change its position, thus, the distance between the biggest cog and the pulley will not change.

Derailleur design should not influence the answer to my question because I assume I don't change B screw adjustment, thus, I don't change derailleur position - the question is whether shifting is still ok in this situation..


Finally, I think that if you adjust B screw to (let's say) 5 mm distance to the biggest cassette (say max 36 teeth), then you will always have the same distance to the smaller cassette (say 12 mm to max cog of 28), regardless the type of derailleur and chain length. Whether that distance of 12 mm in my example is still ok for good shifting - this can only be answered by practical testing.

But, if it happens that the producer of the system recommends the same combination of 5 mm for max 36 teeth and 12 mm for max 28 teeth, then we can simply assume that he did the test for us and found out that changing cassettes within the recommended interval can be done without readjusting B screw, if this adjustment was done once at one of the extremes (5 mm for 36 teeth or 12 mm for 28 teeth).

Complicated...