Hi, I've worked on my own bikes for a while now and am not a great mechanic, but I had a b-screw question. I know (from reading Sheldon, etc.) what it is supposed to do, but I've had 2 bikes where it seems like adjusting it does absolutely nothing, or pretty close to nothing.

In both cases, I've run a long cage mtn-type RD, a wide range cassette (12-32 or 11-34) with a double crank (38-52).

Does my b-screw not really do much because I'm not running gears that exceed the RD chain wrap? (i.e. - not running super slack gears like 22-34t or something).

Does it mostly matter when you have smaller chainrings and more slack in gearing?