Originally Posted by Charles Wahl

Another question: I have the later model type (not like those shown above) that have the cutout in the lever. All of the ones I have seem to have a nylon washer at the end of the screw, that makes it difficult (but not impossible for a determined tinkerer) to remove the screw. Does that washer serve any other purpose than to keep the screw from falling out? They look pretty chewed up to me.

Originally Posted by Charles Wahl

From looking at these, and the diagram such as above, it seems to me that the operating principle is that when the lever is pushed the way that pulls derailer cable, the bushing (that I can't remove) is turning in a direction that is "opening" the spring (easier); while when the lever is moved in the direction that slackens the derailer cable, the bushing rotates so that friction tightens the spring against it (harder).

Is that a correct assessment?

What isolates the tension screw on the outside from the operation of the rest of the assembly, so that repeated use of the lever doesn't tend to loosen the screw, as is common with the old standard Campagnolo shifters (and probably most simple, as opposed to Simplex, ones)?

Or do they have to be tightened at regular intervals too, only with a tool?