[GDTRFB]

Yes I know that the best way to get the B-screw setting correct is to measure.
But once the chain is on, are there any telltale signs that the B-screw is too close or too far away from the cassette?
I have new Red, and I believe that the B-screw was too far from the cassette. Shifts from bigger to smaller cogs were fine, but shifts from smaller to bigger were noisy, as if the chain was being plucked like a guitar string.
I compared it to my Force bike, and the Force was much quieter & smoother.

 

[looigi]

Yes I know that the best way to get the B-screw setting correct is to measure.
But once the chain is on, are there any telltale signs that the B-screw is too close or too far away from the cassette?
I have new Red, and I believe that the B-screw was too far from the cassette. Shifts from bigger to smaller cogs were fine, but shifts from smaller to bigger were noisy, as if the chain was being plucked like a guitar string.
I compared it to my Force bike, and the Force was much quieter & smoother.

The correct way is to measure with the chain on, though with most SRAM it doesn't matter because the upper jockey wheel is coaxial with the cage pivot. This is not the case for most Shimano.

Anyway, Shift through all the cogs and see where the upper jockey wheel get closest to the cogs, which has always been the largest cog, in my experience. There needs to be enough space between the jockey wheel and cog for the chain to derail without getting jammed between them. This is usually specified as 6 mm between the tip of a cog tooth and tip of the jockey wheel tooth.

If you're using a pre 2012 Red power dome cassette, these are notably noisier/louder than anything else.

 

[MikeWMass]

Too close, won't shift to larger cogs, too far, won't reliably shift, may take two clicks to shift one and may not go all the way up or down the cassette (I am assuming you have an indexed system; with friction shifters too far just means you have to overshift and then trim).